What are people in Dorlingo following for?
What's this helpful?
When there were Duolingo clubs (ended May 2019) you got to know a lot of people. You can do a "How are they doing now?" kind of follow up, I guess.
Following people has no function whatsoever.
I guess to keep an eye on those people who stood out for some (positive) reason. In future there may be more functions, לדוגמה ליצור חבורת דיון או משהו
Well on the lessons page (on the website) it shows how you're doing this week / month / all time in a mini table against people you follow.