I don't think there's any particular requirement to socialize when at a "third place". So if you just go sit in a cafe, coffee-shop, bar, etc., and work with your headphones on the entire time, you're still enjoying a "third place". Some people (count me in this bucket) get "something" from simply being around other people, but don't necessarily want extensive engagement with those people - at least not on an ongoing basis. Sometimes you just want to listen to the Youtube video you're listening to, or finish the code module you're working on, or whatever. :-)

Me, I like sitting in the cafe at the local Barnes & Noble. I get to enjoy coffee, books, wifi, and a pleasant ambiance. And for the most part I can regulate how much I socialize with the people around me. I say "for the most part" because I'm such a regular there that I've gotten to know a lot of the employees and other regular visitors and have formed friendships with a number of those people, to the point that sometimes when I go in there I have a lot of people coming over to chit-chat. Which is OK in that they're people I enjoy talking to, but sometimes if I'm really trying to get some specific task done, it can be a little bit frustrating and I struggle with how to disengage from them without seeming overly rude. Still, on balance, I get a lot out of hanging out there.

I'm like my cat, in that I like to be near people, but not necessarily engaging. Sitting in a coffee shop doing my own thing is really nice sometimes.

I think in the future, zuck is hoping it's the metaverse.

Currently, for me, it's been hiking trails, quiet cafes, and bookstores where I can be in public, but generally avoid large crowds and if there are interactions they're most likely one on one.

I don't think it's really changed. There have always been introverts. So: "churches, cafes, clubs, public libraries, gyms, bookstores, stoops and parks", to name just a few. The difference is that there's a new third place called the internet that has replaced those for a lot of people, with many negative consequences and a few positive ones.

Obviously it depends on the introvert, but any quiet, casual space where the focus isn't on socializing. So for me, some places that come to mind are a climbing gym with plenty of space for lounging, makers space, a bookstore with a cafe, library, an outdoor public mall with seating and food, and maybe a dog park.

Before Discord was mainstream (2016-2018) there were some really fun public voice chats but now its 90% minge and not what it used to be. I've also met some pretty crazy people on the voice chat in Valve games and occasionally IRC. I go on SpaceHey a lot now to find new people to talk to.

A makerspace

Libraries

Online forums, libraries, bookstores.

Mine is parks, and nature generally