Del.icio.us tags aren’t like meta keyword tags because of the Del.icio.us Lesson. Meta keyword tags provide no personal value whatsoever. All of their value is social. They’re for aggregation engines to find and tell other people about. In other words
A page full of buttons for bookmarking (simultaneously, if desired) to sites like del.icio.us, magnolia, digg, furl, spurl, reddit, blogmarks, feedmelinks, and so on.