Not necessarily, but if you're blogging under that domain people are going to assume that's your name or something. Which if it is, is fine - someone got to the .com of my last name before I did (so I had to register the .net), and that's always a good resource to have. Otherwise to me it just seems kind of confusing.
It is not my last name, actually my last name is too complicated to even type it into a browser (cserny) :)