Rademacher's site takes data from Craigslist apartment listings and plots them on a Google map, creating a very useful site that neither craigslist nor Google had offered. Yet, Rademacher's site would have been impossible had it not been for the information supplied by these two popular sites.
One could argue that Rademacher's site is parasitic, but don't worry. He isn't having to defend himself in court. Quite the contrary. Not only are both Google and Craigslist OK with him doing it, they're downright supportive. Craigslist founder Craig Newmark has been quoted as saying he's "appreciative" of the effort. Google must have been impressed. Rademacher now works for the search giant.
HousingMaps.com is an example of a new type of Web site called a "mashup," which is a unique site that uses data from two or more other sites to add value to both of them. It's a relatively new phenomenon that some people are calling "the next big thing." Dan Gillmor, director of the Center for Citizen Media (housed at both Harvard and Berkeley) calls mashups "the Legos of the Internet except they don't all come from Lego. Anyone can plug anything into another piece."
The term mashup comes from the music world where it means the combination of two or more songs to create a new musical work.
Although many Web operators are more than happy to have their material "mashed" into another site, whether a mashup is legal or not depends, in part, on the cooperation of all involved as well as ones interpretation of our copyright laws.
At a recent two day "Mashup Camp" a few hundred people who care about mashups gathered for what organizers called an "unconference." Unlike most tech conferences, attendance was free and the agenda was organized on the spot by those in attendance. The conference was informal, unstructured and very democratic. Support came form corporate sponsors including eBay, Microsoft, Amazon, Google and Yahoo.
"None of the big players want to be left out of the game," said John Musser who runs ProgrammableWeb.com. "They're here to figure it out because they know there's a business model in there to be had whether it's advertising based or whatever it is, and they all want to be in the game. This is the big battle ground. This is going to be trains colliding."