One of the most promising features of open source is the ability to reuse code. One conspicuous example is Apple's use of KHTML, from Konqueror/KDE in its Safari browser, or Linspire's use of Mozilla with its multiplatform Nvu "Web authoring system." A lot of fun things can happen when talented hackers have the opportunity to build on or extend other hackers' code.In the interest of making it easier to find and reuse code, Darren Rush has founded Koders.com, a search engine for source code. The Koders.com search engine allows developers on the prowl to search for code, and to narrow the search by language and/or license. Want to find a snippet of GPL'ed code to enhance a PHP project? No problem. A Perl script to convert PDF to HTML? Piece of cake. According to the Koders.com homepage, the site's index includes 125,112,016 lines of code. Rush is looking at two ways to make money off of Koders.com. The first is ad revenues from the public website, the second is to sell the search engine to companies to use privately with their own archives of source code. While I think that Koders.com is an excellent idea, I'm not sure that there will be enough traffic to generate big bucks through ad revenue. However, using Koders.com as a testbed to sell the idea to companies with large repositories of code (think Adobe, Cisco, Oracle, IBM, etc.) may be a winner.