When to come back over the top of a continuation bet?

[Yahweh]

The continuation bet seems to be common place now days. Nearly everyone is attempting it, so when is it correct to come back over the top to take the pot down right there?
I realize that knowing your player and his/her liklihood of making the continuation bet is very important(The cards they normally play), but online you rarely get that luxury unless you have good book on them or you've seen them do it recently.

Assumming your opponent(heads up) is a stranger. Is it a lucrative proposition to try it often(without a hand), sparingly(without a hand), when you have a few outs or only when the flop hits you?

Will the money you make by trying this outweigh the money you will lose when you get called?

for me id say alot of my decision is based on the size of stack i have and the % of which i'll have to commit to try to steal. besides your obvious answer "knowing your player"

[smoore]

I play micro tournaments and SnG's.

This is where I semibluff. If it is JUST a cont. bet then I usually take it there.

If the flop really hit me and it's already HU I'm inclined to flat call as long as the opponent is capable of making a cont. bet for a cont. bet's sake. Lots of people that seem to know how to play the flop totally lose thier s*** on the turn and river.