Semantic distances between comments in online newspaper forums increase over time

Max Pellert (https://mpellert.at)

Barcelona Supercomputing Center

https://mpellert.at/
ccs_talk_09_25/
ccs_talk_09_25.pdf

DerStandard

DerStandard is a major Austrian newspaper, online user can post below news articles

We created a dataset from the platform that spans ten years (2013–2022)

Includes over 75 million user comments, more than 400 million votes and detailed metadata, also on articles and user interactions

(Dis-)Similarity of postings over time

We embed the text of each posting with “KaLM-embedding-multilingual-mini-v1”

Next, we compute cosine similarity of all pairs of postings below each newspaper article

We average by month of each year

To check for divergence of contents, we compute similarity between short text summaries of each pair of article in each year

A proxy for polarization?

Interesting phenomenon that could be an artifact

Like singular topics that overlay everything for some time at least (COVID-19 or Russo-Ukrainian War)

But dominating news topics hardly a new phenomenon and that should also affect article summary similarity?

Otherwise, it could be a revealing trend

Some sign of polarization?

If yes, the trend should differ between article contents –> we can make use of the topical tags on articles provided by the platform

Topic Tag (G) Topic Tag (E) Average increase of distance (in 10^−4)
diestandard genderissues-political 2.934
diskurs discourse 1.716
etat media 1.134
gesundheit health 3.093
immobilien real estate 2.496
inland national (domestic) 1.822
international international 1.342
karriere career 2.424
kultur culture 1.980
lifestyle lifestyle 0.955
panorama reports 1.157
sport sport 1.982
web web 1.632
wirtschaft economy 2.072
wissenschaft science 1.804

Further analyses

I speculate that within-group similarity may have become higher over time, leading to higher dissimilarity between groups and an increasing overall mean

To compare groups, we have (ideological) user factions based on signed networks

Also checking for Simpon’s paradox (unlikely)

Definitely, better metrics needed

What are the mechanisms behind that?