Donkey just reminded me of another incidence I had in chat.
This was years ago, and the user is no longer here, at least, not under that name.
I'd been spending time in a particular chat room for several weeks. We had a smaller group that gathered there every night and so we really got to talk to each other on a more personal basis. One of the guys in the room starting PM'ing me a lot, for several nights in a row. He seemed nice enough, and we even eventually talked on the phone.
Not long after that, one of the girls in the room (I was friends with several of the girls there) wrote me and said, "By the way, beware of X. He talks to every girl here and is looking for anyone who says yes to being his girlfriend. He's already tried talking to me and all my friends here." I hadn't told her that yes, X had been talking to me. And, after one "real" conversation on the phone, he never talked to me again, which I felt confirmed what my friend had told me.
Yes, I know it borders on gossip.
But when people I've known for a while through both laughs and trials give me a warning, I pay attention.
I never had that much of a close-knit circle on the dating sites.