The spots, which quietly launched at the end of the summer, start with the keywords "string theory," "Egyptology," and "astronomy" being typed into a search bar; as the terms are typed in, videos that relate to the subject appear behind the search bar. The spots end with the tagline: "Google is proud to support NOVA in the search for knowledge."

Google did not use an agency for the spots, said a spokeswoman; rather, the search giant worked NOVA to create the ads.

Jupiter Research analyst Gary Stein said any move toward branded advertising targeted at consumers marks a significant change in marketing strategy. "The fact that there would be any sort of a commercial, even a short little spot, is not what they've done in the past," he said. "It's one of those things that's become a badge of honor among Web 2.0 companies--to not spend any money on advertising."

For the most part, Google's strategy is focused on public relations and not advertising, Stein added.

Stein noted, however, that Google has in the past run branded advertisements in outlets like NPR, but they never appear to be targeted at consumers--the search giant's radio ads, for example, were recruitment ads, inviting interested programmers to send their resumes to Mountain View.

Search expert John Battelle, who authored a book about Google, added that public media outlets like NPR and PBS are a natural place for a firm like Google to test out branded advertising. "I think they're doing it in a medium that's consistent with the brand ethos--a sponsorship as opposed to pure consumerist advertising," he said. "It seems like a perfectly natural place for them to try a new voice, so to speak."

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