Well do you think it is because on various website that you may post at, your username might be hyperlinked to your various domain names?
For instance when I post on
blogs, my username is hyperlinked to my domain, kbkmarketing.com. Here is an example at WPN:
http://videos.webpronews.com/2006/12...e-of-pagerank/
Of course kbkmarketing.com is going to rank for the keyword "jaan kanellis" if do enough posting.