@ArtOfCode In fact, I received in my inbox invitation to joint chat here. I am not sure whether some inexperienced user invited me into this room by mistake or whether invitation was moved here together with the messages.
The invitation does not show who invited me to chat. (At least I did not notice anything like that.)
And I do not know whether other users received invitations too - but it seems to me at least understandable that if somebody was invited to a chat room, they are tempted to respond.