Given that it's a .jp subdomain, it's likely geared towards Japanese. Denisu is a valid shortening of DNS - the characters to spell it in katakana would be デニス, and potentially easier to remember for Japanese than "whatismyip," a fully qualified english query. Unless someone out there who knows more about Japanese than I do (admittedly, very little) can confirm that デニス or でにす is an actual word (google translate detected でにす as a phrase, giving me "su to the," which makes sense grammatically..)<p>Funny enough, it's also the romanjification of "dennis" (one of the first hits on google for it is dennis rodman's japanese wikipedia article).