Online Testing and Optimization Solutions: Quick Guide to SiteSpect
SiteSpect is not a tag-based solution, which is perfect for non-intrusive testing. In other words,you don’t have to add snippets of code to your site that a vendor claims won’t (but we all know occasionally do) mess up your pages.
Also, no content is stored on the SiteSpect system itself, just for testing. And soon, SiteSpect claims you will be able to store page variations within your own SiteSpect install.
Read more: http://www.marketingexperiments.com/blog/analytics-testing/sitespect.html