Urchin was what gave birth to Google Anayltics. Google bought Urchin Software in 2005 and morphed it into Google Analytics, the on-demanded hosted solutions. Urchin was still kept alive to date as a log file based on-premise solution. Google has not decided to shut it down too.
You can read more about it on the Google Analytics offical blog, http://analytics.blogspot.com/2012/01/end-of-era-for-urchin-software.html