Have you tried microstock photography?

Time for a photography-business-priority topic, following up on Yvon's Pentax DSLRs blog opening up the topic of microstock photography for discussion. What is your experience with microstock photography? Please feel free to leave a comment here or at Yvon's blog, and share as little or as much as you like. If you have already written about it on your blog/website/forum, or are planning to write about it, also please feel free to let us know using the contact form or comments.