Steve Cohen points out that Amazon has a number of RSS feeds. I like it, I like it! He's right that it would be niftier if it were customizable, but it's still rss-alicious. Note that what the feeds deliver is "a headline-view of the top 10 bestsellers in that category or set of search results."
The The U.S. Consumer Product Safety Commission just added an RSS feed for its recall information. What a terrific way to stay up to date with this information. Kudos! The feed is here: