No. Threads is defunct and corporate. Other forum areas came and seemed to mostly go more due to non-software issues (e.g. squabbles, and iirc is it discuit that is still ongoing, but still needing invitations? Whichever one it is, if my memory is failing on the name, it has decided not to grow further beyond what it is now.)

Lemmy has the most polished codebase but turns mainstream people away with its political extremism, though many people worth talking to hide out amidst all that, having merely blocked it and staying in a different “corner” of the Fediverse. Sublinks promised to be different while also being backwards compatible with Lemmy, but nobody seems to have heard of any progress made for months.

PieFed is exciting, has SUPER responsive and active devs, and currently seems the best poised for the future, after it develops an API that would allow the former Reddit apps to work with it just as readily as with Lemmy. Though currently its web UI is an odd mixture having more fully functional features than Lemmy while also lacking a great deal of the more foundational polish for more active threads.

Oh, there is Mbin though, which is pretty great. Technically it should count since it accesses both Lemmy and Mastodon content. Like Lemmy it both has and also lacks a great deal of features - e.g. PieFed has categories of communities, making discovery by a new user much easier, and PieFed allows you as a non-admin user to block all the users from an entire instance (let’s say hexbear.net or Lemmy.ml) while neither Lemmy nor Mbin allow that. Some Lemmy apps do this though, and more. Mbin has an API, and e.g. the Interstellar app works with it, though it may not matter since both Mbin and Lemmy are federated with one another.

And to be comprehensive, there’s also the Tesseract alternative front end UI to Lemmy, as implemented on e.g. dubvee.org. iirc most people using “Lemmy” are using an app rather than the base Lemmy web UI, so that if the backend were swapped out with Sublinks, Mbin, PieFed, or something else implementing the ActivityPub protocol then people may hardly notice. Except for those additional features that some have but not others, and noticeable effects such as when blocking someone if they can continue to silently talk at and invisibly stalk you around the Fediverse, that may make a difference to users in their choice of back-end.

Anyway, most people are still on Reddit. It’s not merely from habit and the fact that everyone else (especially for niche interests) is still there as well. We out here on the fringes have that “early adopter” mindset that will put up with a lot that normal people simply won’t. They remain there bc they legitimately like it more than here.