It’s hard to get an exact number but you can extrapolate based on the growth of Lemmy in the last few weeks. While not record-breaking, it is quite an impressive growth.

Also note that not everyone who left Reddit came to Lemmy. There is also Kbin, Tildes and alternative. Some never really left at all.

I think the real damage done to Reddit (ultimately by themselves) is showing the world that there are real alternatives (even if a bit rough around the edges). They are materializing and growing as threats and if Reddit doesn’t step up their game, they could be in some real trouble.

The other possibility is that some other company might step up and build a Reddit clone, much like what Meta’s Threads is to Twitter, once they see that there is blood in the water and a potential to displace Reddit as the “frontpage of the Internet”. Heck, even Threads is built on the Fediverse, maybe a bigcorp-backed Reddit clone might be as well.