I think the big advantage of meetup is a lower "creepy factor". If I'm going to a scheduled, planned event to do something specific then that has natural boundaries - and then often a subset will go to the pub afterwards where things get a bit more informal, but you're under no pressure if you don't want to. I do like this idea because making new friends is hard, but I'm worried meeting people who have been "matched" with me would turn awkward.