It turns out that at least with one of my arguments when discussing whether to set up a donation button I wasn't completely wrong: There are significantly less donations than comments, so that on a typical day I either get zero or one donation. What caught me by surprise was two things I hadn't counted on: There apparently was pent up demand to give me money, so on the first two days I got more than a dozen donations. And it turned out that my readers are more generous than I would have thought. The median donation was $10, and several people even donated $20. Thus overall I received more money than I had expected, and more than I would have made with Adsense or similar advertising schemes.
Thank you all very much for your donations. They are much appreciated. Some commenters were discussing donations in terms of "need". No, I don't "need" this money to live, you don't "need" to donate anything, and the donations aren't "needed" to keep me writing. But that lack of need makes them only more valuable in my eyes, as I consider them as the most sincere tokens of appreciation you could hope to get on the internet. Of course the money is nice to have, and I'll try to finance interesting things for the blog with it, but it is the appreciation that counts the most for me.