A biography, a (micro)blogging site, and a billion dollars

Did you hear that media conglomerate Yahoo! just bought wildly popular microblogging site Tumblr? Well, it happened. More details here:
http://online.wsj.com/article/SB10001424127887324787004578493130789235150.html

Much of the media coverage around this event has focused on the financial aspects of the deal and on how these two companies will change and influence one another. But let’s take a step back and consider a question that is probably more pressing for our young readers. How did a 26-year-old high school dropout start a company that just sold for $1.1 billion?

We can help answer that one! Check out David Karp: The Mastermind behind Tumblr, from Lerner’s Gateway Biographies series.