I joined Delicious about a year ago. I find myself using it in spurts and then getting out of the habit for awhile and then getting back into it. I really do enjoy it when I use it, and I love the fact that I can get to my bookmarks from any computer. It is also easy to find what I have bookmarked, and I am not looking all over my computer. It is a great way to organize my bookmarks, and because they are public I love how I can read what others have tagged. When I get into doing that and reading others' tags, time really flies by and all the sudden I realize an hour has gone by. It has been very useful to find great sites from other people.
I think the biggest advantage of using Delicious is that you no longer need to use the browser that is running on your own computer to find your bookmarks. I like the fact that all the information is in one place and it comes to you. It really makes it so much easier to research and find information. I like how you can easily access the most recent and popular items. I definitely use it for my professional life. I have found wonderful ideas for my classroom, and I have also found great ways to integrate technology into a lesson to make it better. I definitely think Delicious is a good thing for teachers and the education world!