Now, when you read a thread, there a list of 'threads you might like' at the bottom. And they're old. So people are seeing titles that look interesting, clicking on them and responding.
I was on the one about the mum who wanted her son to let her know about his flights, and below the last post is a link to one about a girl moaning about her mum wanting to know her travel details. But it's six months old. Presumably that's happening all over the place