Back in the late 90s I was part of a fannish mailing list of writers. There were a lot of us, but about a dozen regular posters. We encouraged each other, read stories and bits of stories, critiqued (lovingly), and generally enjoyed ourselves in a productive way. The list became another, differently-named list, and then a blog community which didn't last too long. Gradually though, we found each other online anyway.
Fast forward to the mid-2000s, where I was going to art school in London. One of the writers was going to visit, she posted on her journal. Would anyone like to meet up? Yes!!!
We spent a great couple of days going through the free museums, and clubbing at night. This is still one of my fondest memories.