Reddit

This is actually an interesting question. First thing to note is that any estimation is by accounts, not by actual people (one person can have multiple alts on both). Honestly I don’t think it’s possible to have meaningful estimation.

That said, I think the first task is to figure out if we can estimate the number of accounts deleted on Reddit during the controversial period (let’s say April when the API change was starting) up til now.

I’m not aware whether there’s public daily data on it from Reddit, but there have been attempts at archiving reddit during this time and of course before. So one can theoretically use the archives to find out “all” existing users. And check the links now via browser (or curl) to see if they still exist, treat that as a good-enough proxy for deleted account.

One may get an estimate of when they were deleted by checking the links in the archives if possible. If not, there’s also Wayback machine that we may use to get a sense, but there are limitations of that.

Lemmy tracks account registration daily, I believe. I don’t know what stats one needs to run but maybe if we can line up the time series of account creation on Lemmy and account deletion on Reddit, we might have some sense of what a lower bound is for those who jumped ship forever.