Tagging and Social Bookmarking

I can see where tagging could be useful, especially if you use more than one computer. By tagging your favorite sites, you would always have access to them without having to remember them or have them written down somewhere. Tagging would also make it easier to share your information with others who are interested in the same things you are, or who are researching the same topic. Even advertisers could make use of tagging to sell or launch a product of interest to a particular group or profession.