How much do Donate buttons raise?

I wanted to know from anyone who has a Donate button on their site how much money that brings in? A lot of open source project sites seem to have them and such. I was thinking about adding one to one of my sites.

I have a few electronic how to sites and always get emails asking for help with school projects and such, I also have 2 charity sites and a couple random tool type sites. Most of my sites have adsence on them and do quite well, I don't know if the two together will be bad for the site or violate adsence TOS.

Thanks

In my experience, even if you put it in someones face, bugger all.
Think I had one up for a six months and made about 15 bucks off of it - just be grateful to the people who do dip their hand into their pockets but remember, if you are giving stuff away people will not pay out of the goodness of their heart

Harsh but true (but thanks to the three people who donated to me )

I too had one on one of my sites for a few months, it didn't bring in anything if I remember correctly, now it also depends on the kind of site you have i guess, if it's something that's helping a lot of people maybe you get lucky.. but if adsense id doing ok, i'd leave it at that..

It depends on what it's for. They usually don't bring in much to be honest. Worth a shot though.

Fatboy is dead on, people don't part with their money until they have to. Think about it. When did you last use a donate button?

it totally works. the open source sites are running by these donations. And remember that .5$ is not the fact. The fact is that you are getting it for free. so whether you get is good.