I'm just trying to understand this move.. DDG has been running with ~1 dev for 3 years.. I know that they were adding a second dev, but why raise capital? I don't see what this gets them, over continuing as a lifestyle bus.
What Gabriel has figured out and no one else has is how to build a search brand that people trust and are willing utilize. He seems to have a loyal core of users that come to his site without him paying on a per-search basis. Search quality, as perceived by the user, in as much about brand trust as it is about algorithmic quality. Too many companies focus on tech first and hope that the brand trust will come later (SearchMe, Blekko). Gabriel has actually invented a viable search business model. That's much more novel than his technology.
The interesting question is whether DuckDuckGo's organic user acquisition model can scale with additional resources. They put up one billboard in San Francisco and got a huge ROI -- will that work elsewhere?
Gabriel's been a patient bootstrapper for years and I doubt he'd raise capital on a whim. I'm sure he's got a solid plan for the money, which he doesn't have to make public.