Wikimedia reaches its $16 million goal, Wikipedia to remain ad-free
The donations are for one purpose: to keep Wikipedia ad-free, and having reached its goal, Wikipedia remains the only top-10 site on the Web that is free of ads and funded entirely by donations. The best bit, though, is that even the whole donation process has a Wiki. You can see how they tested various slogans, and just how successful the "Jimmy appeal" was, compared to the other possible banners. Finally, if you're really into this kind of thing, you can see a graph that documents the daily donations from 2007 through to the end of 2010.
In other news, Wikipedia will celebrate its 10th anniversary on January 15th, and if you want a piece of birthday cake, there are parties being held all over the world. Be aware that not all of the events are on the 15th, though!