I think there are plenty of posters who would be surprised to see who they have been chatting to, maybe getting on very well with people they wouldn't think to approach and speak to in real life, across 50 year age differences, etc.
And some threads are lovely, like the weekend pet thread, and everybody would have lots in common and plenty to say
But I also think that without user names on you, sitting down having a coffee, people would get on much better in real life than they do online, for the most part. Largely because people who are deliberately nasty anonymously wouldn't dare face to face, but also because when you see people, you realise they are normal people not monsters, anyway, and feel more kindly disposed to them, even if you disagree