We find phone conversations beforehand certainly reduces the likelyhood of no-shows. If they don't have a mobile, get them to call you. You can usually get a far more honest impression of someone on the phone than you can by e-mail or a chatroom.
Depending on you plans, arrange to meet in a pub to chat and get to know each other first. If they don't turn up, at least you get to have a drink or two to drown your sorrows!
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