In addition to his entertaining series of posts on the early Amazon days, Greg Linden also had a couple of other good dispatches. One on RSS suckage, pointing out that aggregators need to proactively help folks cut through the noise. Another is just a nice pile of links on information retrieval research literature, a couple of which were new to me. I've been working my way through Managing Gigabytes. I don't really need all the compression but the stuff on indexing and retrieval is great.