Most sites (although not all) randomly pick the next card on the fly. So, when you fold 39o preflop, and then the flop comes out 339, there is no reason to yell obsenities like my roommate does. The flop would be essentially different every time, since it is randomly picked on the fly. However, this makes absolutely no difference, and you should stop worrying about it. It is perfectly random, which cannot be said of B&M or home games, where human shuffling causes the cards to not be technically completely random. Despite all of this, online poker is RIGGED!!!!!