Freecycle "etiquette"

Question to Freecycle users. I have quite a bit of things I don't need anymore and I'm thinking of joining Freecycle Brussels to donate them to peope. Those who have done this: how do you pick the recipient? Do you always just give the thing to the first person who answers, or do you select somehow? I have a friend who has given away nice things on Freecycle and she said an ad can easily get dozens of answers in a short time. Another thing: are no-shows a regular problem? Said friend has had her fair share.