Bluesnews.com and Slashdot.org
They haven’t really changed a single bit apart from maybe logo updates, but they remind me of when I was a teenager.
edit: I lied, Slashdot looks a little different on mobile at least.
https://www.newgrounds.com/ is still around and still fun.
Used to use Newgrounds all the time in the mid 2000s!
Want to learn a fun programming language? PureBasic ist great. Mighty, fast and still simple. But not only that, it has a still very active forum https://www.purebasic.fr/english/ where people help each other, present their projects, if big or small, and small talk from time to time. There are even happy birthday threads! The creator and maintainer of PureBasic is also quite active on the forums.
OldWeb
A community for anyone who misses the "old web". Inspired by a post I made asking for examples of websites with an old school vibe. This community can be used to post links to old style websites, directories of websites, etc.