Social Network Graphs: Concepts, Metrics & Tools

Software Engineer
|
June 2, 2025
Social Network Graphs: Concepts, Metrics & Tools

Social networks are more than just connections between people. They are dynamic systems of users, content, and interactions. On platforms like Twitter, Reddit, or LinkedIn, relationships form not only between individuals but also between people and the content they create, share, and respond to. These interactions can be modeled using a powerful abstraction: the graph.

Figure: A social network graph representation

A social network graph represents entities such as users, posts, or comments as nodes, and the relationships between them, such as follows, replies, or likes, as edges. This structure allows us to study how influence spreads, how communities form, and which users or content serve as bridges between otherwise separate groups.

In this post, we explore how to model social media platforms as graphs, explain the key mathematical metrics used to analyze them, and examine practical tools that help turn large-scale social data into actionable insight. Whether you’re trying to detect viral content, map influence, or understand user behavior, social network graphs provide the analytical foundation.

What Is a Social Network Graph?

A social network graph is best represented using the labeled property graph model, which captures both the structure and semantics of social systems.

In this model:

  • Nodes represent entities such as users, posts, comments, or groups.

  • Edges represent relationships or interactions between those entities, such as follows, replies, likes, or group memberships.

  • Labels are used to distinguish node and edge types (e.g., User, Post, FOLLOWS, LIKES).

  • Properties can be attached to both nodes and edges—such as timestamps, content, or weights—to support deeper analysis.
Figure: Example of a simple social network

This representation is widely adopted in modern graph databases and query engines because it allows for flexible, expressive modeling of real-world data. It’s especially well suited for social networks, where the diversity of entities and relationships goes far beyond simple friendships.

What Kinds of Nodes and Edges Exist in Social Networks?

Modern social platforms involve many types of entities:

  • Users or accounts

  • Posts (e.g., tweets, videos, status updates)

  • Comments or replies

  • Groups or communities

  • Hashtags or topics

Edges can represent actions or relationships like:

  • A User follows another User

  • A User writes a Post

  • A User likes a Post

  • A Comment replies to another Comment

  • A User joins a Group

This diversity makes social network graphs heterogeneous in structure, but the labeled property graph model handles it naturally: different node types are simply labeled nodes; different relationships are labeled edges.

Graph Directionality and Weights

The nature of an edge may vary depending on the relationship it models:

  • Directed edges for asymmetric relationships (e.g., FOLLOWS, REPLIES_TO)

  • Undirected edges for mutual ones (e.g., FRIENDS_WITH)

  • Weights to capture frequency or strength of interaction (e.g., number of messages exchanged)

These structural details affect how the network is interpreted and how graph algorithms behave.

Figure: An example of a labeled property graph for social networks.

By grounding social network graphs in a flexible, expressive model, we enable both precise structural representation and powerful analytical possibilities.

Structural Patterns in Social Network Graphs

Social network graphs are not randomly connected. They tend to exhibit structural patterns that reflect the behavior of individuals and groups within a society or platform. Understanding these patterns helps reveal how influence works, how communities form, and how information moves through the network.

One of the most consistent patterns is the heavy-tailed degree distribution. In most social graphs, a small number of users have an exceptionally high number of connections—these might be celebrities, public figures, or highly active accounts. Meanwhile, the vast majority of users have only a handful of connections. This imbalance makes the network resilient in some ways but also highly dependent on its hubs for connectivity and visibility.

Another important feature is clustering, which captures the idea that people who are connected to the same person are more likely to be connected to each other. This phenomenon, known as triadic closure, leads to the formation of densely linked groups or local neighborhoods. In graph terms, this is measured by the clustering coefficient, and it often reflects real-world social circles, such as families, friend groups, or coworkers.

Despite the presence of tight clusters, social networks as a whole often have short average path lengths. This is the essence of the small-world effect, where any two people are separated by only a few steps—even in networks with millions of nodes. The result is that ideas, trends, and influence can travel rapidly, even across seemingly distant parts of the network.

Finally, social graphs tend to have clear community structure. These communities consist of nodes that are more densely connected internally than with the rest of the graph. They may correspond to interest groups, shared identities, or coordinated activity. Community detection is a key task in social network analysis because it reveals the underlying organization of the network—who interacts with whom, and where the boundaries lie between different social spheres.

Social Network Graph Metrics and What They Reveal

To understand the structure and behavior of a social network graph, we need more than visual inspection. We need quantitative measures. Social network metrics are mathematical tools that describe how central, connected, or influential a node is, and how the network behaves as a whole. These metrics are foundational in identifying key users, mapping influence, detecting communities, and evaluating how information spreads.

Degree centrality is the simplest measure: it counts how many connections a node has. In a social graph, a high-degree user may be popular, active, or simply well-known. For example, in a follower network, someone with thousands of incoming connections might be considered an influencer. However, degree alone doesn’t capture how a user fits into the broader network.

Closeness centrality measures how close a node is to all others, based on the shortest path lengths. A user with high closeness centrality can reach others quickly, which often correlates with the ability to spread information or receive updates rapidly. This metric is useful when assessing accessibility or efficiency of communication within the network.

Betweenness centrality captures a different aspect: control over information flow. It measures how often a node appears on the shortest paths between other nodes. Users with high betweenness centrality act as bridges between different parts of the network. They may not have many direct connections, but they are strategically positioned to influence or monitor interactions between groups.

Eigenvector centrality and its variant, PageRank, take into account not just how many connections a node has, but how important those connections are. A node connected to other well-connected nodes will score higher. This recursive notion of influence is especially valuable in ranking users, posts, or topics that gain visibility not merely by volume, but by proximity to other central entities.

Figure: A simple illustration of the Pagerank algorithm. The percentage shows the perceived importance, and the arrows represent hyperlinks. (Credited to Wikipedia)

Clustering coefficient measures how likely it is that a user’s neighbors are also connected to one another. A high clustering score suggests tight-knit communities or social circles. This is useful for identifying local cohesion and can help detect groups where information is likely to circulate but not escape.

Beyond node-level metrics, we can look at properties of the graph as a whole. Connected components identify isolated subgraphs—regions where users interact internally but have no ties to the broader network. Graph density measures how many connections exist compared to the maximum possible, offering a sense of how saturated the network is. The diameter, defined as the longest shortest path between any two nodes, gives an upper bound on how far information must travel.

Each of these metrics reveals something different: who is visible, who is strategic, who is clustered, and how the entire network behaves. In practice, they are often used together—for example, identifying high-betweenness users in low-density regions, or finding highly ranked posts that emerge from specific communities. These measurements are not just theoretical—they drive decisions in recommendation systems, trend analysis, moderation, and outreach strategies across real platforms.

Tools and Techniques for Social Network Graph Analysis

Analyzing a social network graph requires more than knowing its structure. Once the graph is modeled, the challenge is to compute relevant metrics, explore subgraphs, and run queries that reflect meaningful social patterns. A range of tools and systems support this workflow, from low-level graph libraries to specialized engines and query languages.

The first category includes graph analytics libraries designed for metric computation. Libraries such as NetworkX (Python), iGraph (R, Python, C), and GraphX (Apache Spark) offer efficient implementations of standard algorithms like PageRank, betweenness centrality, community detection, and clustering coefficient. These tools are well suited for researchers or engineers who need full control over the analysis process and are comfortable writing code to define workflows. For large-scale processing, systems like GraphX and SNAP (from Stanford) support distributed computation across massive networks.

While graph libraries are powerful for analysis, they don’t provide a convenient way to explore or interact with the graph structure in real time. That’s where graph query languages come in. Languages like openCypher and Gremlin allow users to express complex relationship patterns, multi-hop traversals, and filtering conditions in a declarative way. For example, a query might ask for all users who liked posts written by users followed by Alice, or trace the shortest path between two hashtags in a discussion network. These languages are not designed to compute global metrics like PageRank directly, but they are essential for building, exploring, and refining graph-based investigations.

To support these workflows, many teams adopt graph databases. Traditional graph databases, such as Neo4j or TigerGraph, store data in graph-native formats and are optimized for graph traversal, indexing, and built-in algorithm support. They are commonly used when graph operations are core to the application itself—such as powering recommendations, access control models, or social feeds.

While graph databases are powerful tools for managing highly connected data, they come with operational and architectural trade-offs. Performance can degrade on large-scale datasets, especially when queries involve traversing deeply nested relationships or span multiple partitions in a distributed setup. Integrating a graph database into existing environments often requires complex ETL pipelines to reshape relational data into a graph model, adding latency and increasing the chance of inconsistencies. Additionally, many graph databases are schema-less, which can lead to challenges in maintaining data quality and managing evolving graph structures as applications grow.

An alternative approach is offered by graph engines like PuppyGraph, which allow teams to define and query graphs directly on existing relational or tabular data, without needing to move or duplicate it. PuppyGraph uses the labeled property graph model to represent nodes and edges virtually, based on the schema of underlying SQL data sources. It supports both openCypher and Gremlin for querying, and can execute multi-hop queries in real time. More importantly, it includes built-in support for selected graph algorithms, such as PageRank, connected component finding, and is expanding its library of supported metrics. This allows analysts and engineers to explore their social data graphically, compute influence scores, and extract structural features without setting up a separate graph database.

Figure: Architecture comparison between Graph Databases vs. Graph Query Engine

These tools vary in purpose, performance, and flexibility, but they all aim to make graph modeling more usable and effective. Whether you’re computing metrics offline, exploring patterns interactively, or querying massive graphs at scale, the right combination of tools turns the abstract structure of a social graph into concrete, interpretable insight.

From Relational Tables to a Social Network Graph

Most social data doesn’t start as a graph. It typically originates as structured or semistructured records stored in relational databases, CSV files, JSON logs, or event streams. Tables may capture user profiles, messages, and relationships in rows and columns, while APIs or logging systems might produce nested formats representing actions like posts, replies, or likes.

To perform graph-based analysis, we need to convert this data into a graph model. That means identifying what the nodes and edges should be, how they connect, and what properties should be preserved for querying and computation.

Consider a typical social media dataset with tables like users, posts, comments, follows, and likes. Each row describes an entity or interaction, but the relationships are implicit—captured through foreign keys or shared fields. To construct a graph, we make these relationships explicit. For example:

  • Each row in the users table becomes a User node.

  • Each row in the posts table becomes a Post node.

  • The follows table defines directed FOLLOWS edges between users.

  • The likes table defines LIKES edges from users to posts.

  • The comments table may be used to create both Comment nodes and REPLIES_TO edges between comments and posts, or even between comments themselves.

This mapping aligns naturally with the labeled property graph model: nodes have labels and properties (e.g., a User node with username, signup_date, and location), and edges have types and optional attributes (e.g., a LIKES edge with a timestamp or weight indicating interaction frequency).

Figure: UML class diagram-style depiction of the LDBC SNB graph schema. Note that this schema is for relational data and the social network graph structure is to be modeled. Credit to LDBC Social Network Benchmark (LDBC SNB)

While it’s possible to materialize such a graph in a dedicated graph database, systems like PuppyGraph make it possible to define this structure virtually on top of your existing relational data. Rather than moving the data into a new system or writing custom ETL pipelines, you specify the graph schema through a configuration: which tables correspond to which node and edge types, and how to match foreign keys to graph relationships.

Figure: Graph schema of the LDBC SNB data in PuppyGraph.

Once the schema is defined, you can immediately query the graph using openCypher or Gremlin. For example, you can find all users who commented on posts written by members of a certain group, identify which posts act as bridges between multiple discussion threads, or run algorithms like PageRank to compute influence scores across users or content. These capabilities let you explore the network interactively while also supporting deeper structural analysis. Since the data stays in place, there’s no overhead from duplication, and updates to the source tables are reflected in the graph in real time.

Figure: Running the PageRank algorithm (openCypher query) on the Persons nodes and Knows edges in the LDBC Social Network Benchmark (SNB) dataset (scale factor = 1, 1GB) using PuppyGraph.
Figure: Gremlin query to find the most recent Comments replying to Messages posted by a starting Person, given their ID, using PuppyGraph.

This model-driven approach lowers the barrier to entry for graph analysis. You can iterate quickly on different graph structures, experiment with relationship definitions, and apply graph algorithms to real-world social data—all without restructuring your data architecture.

Conclusion

Social network graphs offer a powerful and flexible way to understand the structure and dynamics of modern online platforms. By modeling users, posts, comments, and communities as nodes, and capturing their relationships through labeled edges, we can move beyond raw records to uncover deeper patterns of behavior and interaction.

The graph structure enables precise mathematical analysis. Metrics like centrality, clustering, and path length provide insight into visibility, cohesion, and influence. These measures are not just theoretical, as they help identify key users, detect tightly connected groups, and understand how information flows through a network.

Building and analyzing social graphs no longer requires reinventing infrastructure. Tools like graph analytics libraries, graph databases, and real-time engines provide the building blocks for expressing queries, computing metrics, and scaling to real-world data. And with systems like PuppyGraph, it’s now possible to define and explore these graphs directly on top of existing relational data—without the overhead of data movement or duplication.

If you’re ready to move beyond tables and explore the structure of your social data as a graph, try the forever-free Developer Edition or book a demo with our team.

Sa Wang is a Software Engineer with exceptional math abilities and strong coding skills. He earned his Bachelor's degree in Computer Science from Fudan University and has been studying Mathematical Logic in the Philosophy Department at Fudan University, expecting to receive his Master's degree in Philosophy in June this year. He and his team won a gold medal in the Jilin regional competition of the China Collegiate Programming Contest and received a first-class award in the Shanghai regional competition of the National Student Math Competition.

Sa Wang
Software Engineer

Sa Wang is a Software Engineer with exceptional math abilities and strong coding skills. He earned his Bachelor's degree in Computer Science from Fudan University and has been studying Mathematical Logic in the Philosophy Department at Fudan University, expecting to receive his Master's degree in Philosophy in June this year. He and his team won a gold medal in the Jilin regional competition of the China Collegiate Programming Contest and received a first-class award in the Shanghai regional competition of the National Student Math Competition.

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