Ever wondered if someone was watching your domain availability searches? Have you ever checked a domain and it's available but when you go back the next day to register the name it's been mysteriously taken? This may be the culprit:
http://www.eweek.com/article2/0,1895,1991365,00.asp
http://www.eweek.com/article2/0,1895,1991365,00.asp