Just found a book about Flexible Solar Cells. I found it admittedly by vanity search;-) In chapter 4 (about organic solar cells), several of my figures published 
in this blog are used.
Of course, I am very happy that my figures are liked and used, and also happy that I was referenced (my name and the blog are mentioned below the respective figures, and really also appear in the list of references ;-). However, I was somewhat surprised about not having been asked for the permission of the images’ reproduction. I even could have supplied them in high resolution.
By the way, if you want to have a look at the book (yes, free advertisement… maybe I get a copy of the book as appreciation;) , you can find it at google books (hope the links works..) and also at Scribd, although for the latter link, I am pretty sure that the book pdf is published without Wiley’s permission! Disclaimer: all links go to external sites, they are just for your information. [Update 7.7.2009: the book pdf on Scribd was deleted at the request of John Wiley and Sons.]
So, once again, I am happy if you use my material and give me credit, even if you do not ask. But please do!
P.S. One of my photos from this blog (saved at flickr) was also published (with my permission;-) in the Schmap Boston Guide.
Notes on Disordered Matter 
Oh wow, that is certainly not okay! Most people would not be as relaxed about it as you have been. On the bright side, they helped spread your fame.
Fame? Don’t think so;-) but possibly an advertisement. So as you say, in a way both sides profit from it.
P.S. awesome crab pic!