As I browsed through delicious I didn't really understand the whole idea of tagging and bookmarking things. I have been so used to just 'Googling' everything and used that to narrow down my search for different things. Now that I went through delicious I can see how it makes this process a little easier for searching. Even more important is that you can set your own tags and bookmarks on anything you want and add it to the never ending lists of other content.
I would say that this is an easy and convenient way to tag items at your own risk. This idea of tagging is essential for the web to work and your input may be the missing link for someone else on the other side of the globe. Since research from the web is one of my main resources I would say that delicious is a valuable tool in this process. It's easy to use and I can find almost anything with it. The ability to research with this tool seems more practical and you are given a broader variety of results for whatever you're looking for.