In my mid 20's, i'd come back from the pub drunk, login, search for girls online now near me and send them messages. Was usually somebody drunk at the other end, had a few fleeting relationships from that.
Nothing since, including Facebook, has had that same immediacy.
Anyway, it was more about talking than about romantic relationship. Not many people expected to ever meet their virtual friends.
You can definitely ruin that, for example, if you do not randomize well enough and a small subset of user base gets too much attention.
Remember, this was the internet back when men were men and women were men and children were FBI agents.
Also, I have this feeling that it's much harder to disguise your gender in Russian than it is in English. First of all, everybody has it as first language with all its nuance and can guess a lot of things about their penpal. Discussions are also deeper, making it harder to fake.