How "Free Bitcoins" sites work?

[Envite]

I have seen that some places give bitcoins for free, once an hour, or once/12h, etc.

How these sites work? Which income sources do they have? Why do they do this?

I can simply not trust they're just nice people.

[xxjs]

I have seen that some places give bitcoins for free, once an hour, or once/12h, etc.

How these sites work? Which income sources do they have? Why do they do this?

I can simply not trust they're just nice people.

Maybe nice people, maybe they believe that getting in a newcomer will push up the value of their remaining bitcoins, or maybe they are just stupid.

[nobbynobbynoob]

You're not getting a free lunch. The sites are riddled with ads. Each impression may not net much revenue, but add up all the views by "greedy" peeps coming to grab "free" microbitcoins...

[Flip Bitcoins]

You're not getting a free lunch. The sites are riddled with ads. Each impression may not net much revenue, but add up all the views by "greedy" peeps coming to grab "free" microbitcoins...

This guy's got it right. They use any form of advertising that brings in revenue.
(Banners, text-link, popups, captchas, etc...)

These make them much more than the few fractions of pennies they give out.