Okay, the terms "mailing lists" and "newsgroups" are not used much anymore. But if you want a fix of discussing and interacting about Friends, I would suggest this Reddit subreddit:
https://www.reddit.com/r/friends_tv_show/
Though... be warned, a lot of the posts there are people bringing up the same things over and over, or just hating on the characters. But some of the posts are really fun!
If you have a USENET newsgroup reader
then this link may still work. I'm not sure. "USENET" was kind of a Reddit from decades earlier: