There's a magical moment when an unfamiliar piece of information--say, an address or an image--produces a flash of recognition, when we suddenly know where to place it. That happened to Paul Rademacher in April 2005, when he fired up his hacked version of the brand-new Google Maps site. To ease his housing hunt, Rademacher had deciphered, then modified, the JavaScript behind Google's application, creating a version that retrieved data from two different sources: Google and craigslist, the popular classified site. The result was a hybrid page that displayed Google's familiar map and scattered across it icons indicating houses for rent around San Francisco.

Rademacher's new picture of the world--or at least of selected cities--took the Web by storm. Even Google employees wrote on a company Web page that his site, housingmaps.com, "blew our minds right off our shoulders." Thousands of people realized that Google's maps were a giant canvas on which they could doodle, taking the locations of crime scenes, favorite restaurants, or cheap gas stations and creating online tableaux for all to see. But more than that, Rademacher had shown a way to combine data and tools from completely different websites to create something new. One blogger called it a "mashup," a word DJs use to describe the mixture of vocal and instrumental tracks from different songs, and the term stuck.

For Rademacher, there's a moral to the story. Innovation is possible only when companies let you tinker with their creations. Too many good ideas are squandered, he says, because the tools needed to realize them are locked away: "To this day, there are very few technologies that are open." Creating open technologies is Rademacher's new passion. In September 2005, he left his job developing animation tools at PDI/Dreamworks Animation to pursue that passion at Google. His projects there, he says, are still "under wraps."

--Daniel Charles