Title basically. I was here at the very start of it all and really enjoyed it. However I felt it lost its uniqueness within a few months of mass migration and started turning a bit like reddit again so I deleted my old account. However Reddit has only gotten much much worse since, and Lemmy has stayed about the same. So here again.
Initially, it was not stable. Lots of outages and issues with spammers, DDOSing, CSAM, etc. Those issues are mostly sorted.
Additionally, there was originally a lot of excitement and people trying to rebuild the niche communities they left on Reddit. Unfortunately, those efforts have mostly faded. There simply isn’t a large enough population here to support those niche communities at this stage. Mostly, people have sorted into the major topics that are common (news, politics, technology, etc.). Due to the demographics of Lemmy early adopters I’d say gaming and Linux are also well-supported here. The federated nature of Lemmy makes it difficult for niche communities to consolidate enough contributing subscribers to hit a self-sustaining rhythm.
Despite the initial wave of new signups and the subsequent dip, I think the population is leveling off and stable. This is good, but also not the right long term trend as ultimately it still really needs to grow a lot. Monthly active users is just below 50K. In my view this will have to 10x for the engagement in smaller communities to pick up. It may take years, or it may never happen. A lot of that will depend on attracting more mainstream users.