Jerry Yang calls himself the "Chief Yahoo", and that is about as unserious as it gets.
Windows Live Search changed its name to something less serious to be more appealing to the public. I mean, really, Bing? How serious is that?
Ask.com is about the most sensibly-named search engine. I mean, what do you do with a search engine? You ask it things. That hasn't really helped them corner the market, exactly.
The internet hasn't become any more serious recently. People are still using it for non-serious things (lolcats, 4chan, Reddit, etc) so a non-serious search engine can still attract people, I think.
I think it is harder nowadays to make a fame with a name like this.