Originally called del.icio.us, you can find this web site at delicious.com.
Using Delicious has several advantages over regular bookmarks (or favorites). First, the sites you save are saved to the delicious computer, so you can access from any computer. Once you save a bookmark, you can give it many different tags (for example, my web site here might have 3 ro 4 tags, such as teaching, learning, language, tokyo, kevinryan, japan, computers, and women. I can then search b any of these terms to find the web page I want.
By far the most important, though, is that you can share your bookmarks and tags with other people. You can find other people that are interested in the same kinds of things you are, and look at their bookmarks.
I often get all my students in my computer literacy class to sign up for delicious, and we make a small group to share bookmarks. When we do a research project, we can help each other find interesting sites. They are shared immediately and automatically. Very simple, very powerful.