I don’t see any reference on their blog, but it looks like the Google Reader team did an update to allow more than “100+” to appear. In my opinion this was the worst UI mistake in the product. This little change means quite a bit. Other than that, I can’t see any other changes. Polish is always a good thing.
Update [9/6/2007 @ 5:15 AM EST]: Search was added too. I caught them in the middle of a big update.