I saw this on Hacker News.
https://blogs.cornell.edu/info2040/2015/10/14/the-evaporative-cooling-effect-in-social-network/
https://blog.bumblebeelabs.com/social-software-sundays-2-the-evaporative-cooling-effect/
The first link has a summary with some minor spelling and grammar errors. I was unable to access the second link at the time I posted this.
Some people have been complaining about the quality of posts on this forum and I thought (based on the summary) that this might be relevant.