I saw this last year and had to scratch my head a little. How was presenting a search engine as underground and revolutionary ever going to poach people using Yahoo! and Google?
I thought it might have been a David and Goliath strategy; present your brand as the human underdog and your competition as corporate behemoths and get the alternative-thinking trend setters to start using the brand.
Anyway, I forgot about it until December when the cleverness of the strategy became apparent when I saw another ad.
Privacy International has said that Google's attitude to privacy is "at its most blatant is hostile, and at its most benign is ambivalent" (source).
So, attack Google's perceived weakness: privacy. Make search amnesic. Let it leave no wake. This is precisely what Ask.com now offers. And the new search engine from Jimmy Wales has promised to be the same.
I wonder, as the Internet rhizomatically grows and knows more about us, how this privacy debate will play out. I think we'll see privacy as a growing issue possibly dividing the web between those who don't mind having their eggs in one basket and those who'd rather there was no history of those eggs at at all.