Well you have to try it ! Specialy if you already have a blog and a Delicious account : you have no excuse. There are many things going on about web semantic, like FOAF, RDF, Microformat, Folksonomy, but still almost no application to use them. (RSS being the sole exception.) Flock is one of them. One of the first client implementation that exploit thoses promises.
There is a lot of data on the web and still few mean to exploit them.