I remember, about 20 years ago, having an argument with someone on Slashdot. Then realizing, about 10 messages in, that I actually knew the person I was arguing with. Being able to connect with friends online, being able to make friends through dialogue online... the site was easily the best online community at the time.

Bonus: Even 20 years ago it had better design than Hacker News! (= (Couldn't resist.)