What's Social Bookmarking?
Once you've registered for the service, you add a simple bookmarklet to your browser. When you find a web page you'd like to add to your list, you simply select the del.icio.us bookmarklet, and you'll be prompted for information about the page. You can add descriptive terms to group similar links together, modify the title of the page, and add extended notes for yourself or for others.
You can access your list of links from any web browser. By default, your links are shown to you in reverse chronological order, with those you've added most recently at the top. In addition to viewing by date, you can also view all links in a specific category (you define your own categories as you add the links), or search your links for keywords.
What makes del.icio.us a social system is its ability to let you see the links that others have collected, as well as showing you who else has bookmarked a specific site. You can also view the links collected by others, and subscribe to the links of people whose lists you find interesting.