I've had my first vanisher
Really nice chatting on PoF over best part of a week, nothing vulgar, decent spelling (!), friendly, funny, open etc. Oh and cute photos. He suggested coffee last Sunday and I agreed. Then...
...Silence.
Friday morning he writes to say he has a cracking headache he can't shift. I'm not daft but I didn't explicitly say that I could see what was coming. Just said, drink lots of water, and, it looks like you might be ill over the weekend.
Silence.
Saturday morning he comes back with a cheerful yet bizarre message saying he is feeling much better and outlining his itinerary for Sunday which involved lots of various busyness in the next town, but no mention of meeting as planned for coffee.
I ignored him. Silence for the rest of the weekend. Monday, he sends a message asking how my weekend was, "xxxx". 
He is very rarely online and also rarely responded to info that was in preceding messages, hence me thinking he was deleting as he went/being surreptitous, and is probably in a relationship. Either that or he's one of those that will chat to anyone but doesn't actually want to meet.
Fracking annoying nonetheless.