So if you haven't given del.icio.us a whirl, I highly recommend it. At it's base, it's an online, public, bookmarking system. What's really neat are all the ways you can share, consume, manipulate, populate, and learn about websites etc.
For example, I added the 'popup post to del.icou.us' to my bookmark bar. Whenever I'm on a webpage I want to mark, I click this link, fill in the 'tags' (categories, genres, however your brain comprehends the concept) and it's added to my bookmarks.
So then each user, any category, a user's categories, etc. are all subscribable via RSS. Therefore you can use your news aggregator, or even better "Live Bookmarks" if you're using FireFox. What this does is put the RSS feed as a folder of links in your bookmarks. These links are automatically updated from your del.icio.us bookmarks (or your friends or whatever). *Terrific* for sharing bookmarks amongst multiple computers, handhelds, or when traveling.
*Another* cool thing is the inbox. This allows you to get new links added to your personal 'inbox' on the del.icio.us site based on criteria. Any listing of bookmarks you can 'subscribe' to within the site (Not using RSS). So, I have a inbox subscription to any bookmark that is added that has the tags: apple and hack. To do this, point your browser to:
http://del.icio.us/tag/apple+hack
then click: "Subscribe".
Ingenious!