I was curious as well and just assumed the usual NIH (not invented here) syndrome. Web analytics was so mature before Google bought Urchin and turned it into Google analytics. Since that time countless open source projects have sprung up (pwik was the first that came to mind). Google for open source alternatives brings up thousands of pages of projects.<p>Writing your own is easy for the basic stuff. When you want to move beyond the basics, as Spider Oak will find, it becomes much more difficult.