This is a search engine for code.
Koders makes it easy for software developers to find existing source code that solves many common development problems with our vast index of working source code from a variety of open source projects. In many cases you may find code that solves the exact problem you are working on, and in other cases, you can find an 80% solution - where existing code can be suited to your needs with minor modifications.
Appears to be similar but more complete than what's offered in Safari. I'd be interested in hearing back from somebody who's tried this how well it works.
Update 11/10: Resource Shelf now says where they read about it. The NewsForge article also has a brief interview with Darren Rush, the founder and chief architect.