"Steve Jobs and Willy Wonka to me were just like these brilliant people who had these magical factories where every six months they'd come out with this huge show," David Karp told me a few years ago. "I thought that was like the coolest thing ever. That's what I wanted to do." And now, it seems, he just might have done it.

Karp, of course, is the 26-year-old autodidact who founded Tumblr, the social-networking blog site that Yahoo! Inc. just scooped up for $1.1 billion. Karp stands to make $250 million from Yahoo Chief Executive Officer Marissa Mayer's effort to make her search site relevant again.

Karp isn't your typical Internet entrepreneur. He grew up in New York, on the Upper West Side of Manhattan, and attended the Calhoun School, where his mother was a science teacher. His father, an award-winning composer, wrote the musical themes for "Dateline NBC" and TV broadcasts of New York Yankees games. His maternal grandfather, Ken Ackerman, was a radio broadcaster, known as the "Voice of San Francisco."