I just came across a page today with an iGive button.
That brought back memories: many years ago (or so it feels like to me), I had Eyegive (as it was back then) set up as my browser's start page. I believe the deal was that for looking at the ads, a certain small amount would go to a charity of your choice. You could also integrate a link of your choosing on the start page, which I used to point to my "real" start page—so I'd start out at the Eyegive page and then click through to my real start/links page, giving a charity of my choice a small amount of money each time.
They also had the ability to click through to online shops where each purchase you made (if you came from an iGive link) would send a percentage to your chosen charity; as time passed, this side became much more pronounced and eventually they stopped paying out money to charities for just using the start page feature, and I dropped it because there was no longer any point for me. (I don't think I ever used any of the shopping links. Even if there were more sites relevant to someone in Germany, I guess I'm not the kind to start out at a shopping portal of any kind.)
Wow. Hadn't heard that name in years, but apparently they're still around.