Underthesite.com

Cool little technology-stack database, apparently derived automatically, that indexes by URL and by technology. A lot of knowledge there. Makes me think I should probably archive it or something.

Similar tools from the HNN peanut gallery: http://lineofthought.com/, https://github.com/jpf/domain-profiler, https://github.com/mitsuhiko/probe, http://wappalyzer.com/, http://builtwith.com/.