Hasso Plattner Institut
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Exploring User Comments on Online News

Explore Comments

What is ComEx?

The comment sections of online news platforms have shaped the way in which people express their opinion online. To foster more interactive and engaging discussions, we present our ComEx system for the exploration of reader comments on online news platforms. Central to this system is that potential discussion participants get a quick overview and are not discouraged by an abundance of comments.

More info

Explore Video


Discussion on Australian Fires
Australian Fires
Discussion on Brexit
Discussion on Canada vs VW
Canada vs VW
Discussion on Erdogan and Putin
Erdogan and Putin

About the Project


  • Julian Risch, PhD Student [info]
  • Tim Repke, PhD Student [info]
  • Lasse Kohlmeyer, Student Assistent
  • Alyona Vyshnevska, Student Assistent
  • Ralf Krestel, Senior Researcher [info]

How it works

1. Build Discussion Graph

Each comment is split into snippets and represented by nodes in a graph.
Weighted edges are added based on structural or semantic features.

  • Text similarity (embedding model)
  • Reply to another comment
  • Part of the same comment
  • Timely related
  • Cluster assignment
  • ...

2. Reduce Discussion Graph

There are numerous edge generators populate the graph and filters to reduce the complexity.
You can have a look at the parameters in the API for /api/graph and play with different settings.

Generated graphs are typically highly connected and need to be simplified not only for better readability, but also since processing and transmission of the graph would be too slow.

3. Display Discussion Graph

The fully processed graph is shown in the user interface using a force layout.
Edges are omitted for better readability.


  • Julian Risch, Tim Repke, Lasse Kohlmeyer, and Ralf Krestel
    ComEx: Comment Exploration on Online News Platforms. (Joint Proceedings of the ACM IUI 2021 Workshops co-located with the 26th ACM Conference on Intelligent User Interfaces (IUI). pp. 1-7. CEUR-WS.org) (2021)