The main features include the ability to:
- Store links to favorite websites and add tags to make them searchable and easy to arrange in groups.
- Share favorites with friends, family, coworkers, and the del.icio.us community of users.
- Explore new things. Everything on del.icio.us is someone's favorite -- they've already done the work of finding it. So del.icio.us is full of bookmarks about technology, entertainment, useful information, and more. Explore and enjoy.
Another interesting feature is the "Tagometer" that lets visitors can click on a "widget" that keeps up with on who bookmarked your Web page, when they did it, and how they tagged it.
I think that groups who are evaluating Web sites or otherwise sharing information about Web sites will really benefit from the network functions in del.icio.us as well.