It's another Lemmy. There are several alternative Lemmy's actually: Mbin is another, forked originally off of Kbin, and there was another project Sublinks that was stalled but now is being worked on again. There's also nodeBB, and there was going to be flarum but now I guess that's on hold indefinitely...

The point is that if you are happy where you are at, then you don't even need to care: they all share stuff using the ActivityPub Protocol. Even Mastodon (X/hitter replacement) and Friendica (Facebook replacement), Loops (Tiktok replacement), Pixelfed (Instagram replacement), etc. can all share too - though PieFed and Lemmy (and Mbin and nodeBB) are more closely related, being more or less Reddit replacements, or compatible with that anyway.

PieFed does offer more features than Lemmy - like user polls, user & post flairs, multi-communities that are user-customizable and shareable, etc. But also, the main dev recently and controversially took away people's rights to upvote (hence my joke about fewer contributions from PieFed lately), imposing a confusing and non-transparent quota system for how many votes someone is allowed each day. Like most features it can be enabled or disabled by the instance's admin team, but it is making people wary of switching from Lemmy to PieFed when not just this but other features like it will come in the future - with barely any notice and against massive community push-back.

Then again, Lemmy's main devs are tankies, who promote people on their instance trolling users across the whole Threadiverse calling for the fall of the entire Western civilization and the death of most people therein. So it's not like one software platform is controversial while the other is not - they both are, just in different ways.

But at the end of the day, they all are helping, bc their freely offered FOSS is an enormous boon to us all, who hate Reddit (fuck spez). If you do want to check out PieFed, look at PieFed.zip that has that vote quota disabled and a very sensible admin team. Maybe even make an account, as that sign-up wizard is outstanding, and even use PieFed for a bit as its abilities to discover communities is so much better than Lemmy's - even if you only use that information to let you know which communities to subscribe to on your Lemmy.world main account, it's a nice experience. (And this way whenever your instance goes down due to some technical issue or upgrade, which is rare but does happen, then you'll have another option to jump to for awhile!:-).