I've added some Google Adsense advertisements to my blog here. I have not, however, added these adds to my Wikimedia-related blogs. I don't expect to generate any substantial revenue from these ads, and I'm purposefully keeping them small and unobtrusive.
If I find that they can be used in a tasteful and unobtrusive way, I may extend these to some of the wikimedia-related blogs as well. Money I earn from such ads (and again, it certainly won't be much) will definitely be used for wikimedia-related purposes.