Decomposing discussion forums using user roles

Jeffrey Chan & Conor HayesFriday seminar

8/20/2010Presenter: Asta Zelenkauskaite

Feature-based profiling

Users roles are identified by the features (indicators) to profile user behavior

◦Visualization techniques Downside: used only for small-scale studies

◦Proposed solution: soc net analysis Ego-network analysis and the out-degree

distribution

Data

Boards.ie – the largest discussion board in Ireland

596 forums75400 users 244850 threads 4.3 mln posts

Forums

Optimal number of clusters

Analysis

Weighted directed graph Ego-net graph – reply graph (multi-edge

graph)

20 forums from 01/07/2006 – 31/12/2006.

Features

Initially 50 features, redundant eliminatedStructural features (as communication btw

users)◦Unweighted directed graphs◦From interaction with their neighbors

Reciprocity features Persistence features Popularity features Initialization features

Structural features (operationalization)

◦From interaction with their neighbors Reciprocity features

◦% of bi-directional neighbors (represents the % of the neighbors of a user where there is both in and out edges – they have replied to each other).

Persistence features◦The length of the conversations a user typically engages in

(mean and sd of the posts per thread). Popularity features

◦Ratio of a users’ in-neighbors (% of in-degree) # of replies◦% of the posts where there is at least one reply to the user.

Initialization features◦ Initiated % of msgs by a user.

User role discovery approach

Data cleaning◦Filtering out low-degree, low posting users

User grouping◦Via number of neighbors

User roles

Joining conversationalists ◦ the ones who do not initiate but post replies

Taciturns◦ Low reciprocity (rarely get involved into two-way communication)

Elitists◦ Low % of neighbors w/ two-way communication

Supporters◦ Middle range of the statistics of all features

Popular participant◦ Do not initiate many threads but get involved with a large percentage of

users of a forum Grunts

◦ Similar to taciturns, relatively high levels of reciprocity. Ignored

◦ Extremely low % posts being replied to (not very popular)

clusters

Results: Forum composition

Some forums are distinctively different from the others (eg. personal issues)

Difference in grouping by conversationalists vs taciturns

Some topics determine certain composition

Discussion

Is it impossible to assess the ‘success of functioning’ from the composition of the group?