I use a couple of portal pages (iGoogle and NetVibes). I set these as the default home page for my different browsers on my different computers. When I connect, I start from the same place and have access to a list of web links, RSS feeds, calendar, etc.
One component of the iGoogle page is web history. At this point, I can explore the searches I have conducted since June from this page and ask Google to offer me summaries of my activities.
For example, I think it is fair to conclude that I spend a lot of my time in the evening online.
On June 6, it looks like I was trying to figure out what people had to say about evaluating student blog posts.
It is hard to know what to think about this kind of thing. It is kind of interesting, but it is also kind of creepy.