sitediff (rubygems):   SiteDiff makes it easy to see differences between two versions of a website. It accepts a set of paths to compare two versions of the site together with potential normalization/sanitization rules. From the provided paths and configuration SiteDiff generates an HTML report of all the status of HTML comparison between the given paths together with a readable diff-like HTML for each specified path containing the differences between the two versions of the site. It is useful tool for QAing re-deployments, site upgrades, etc. 
Keywords: comparison|diff|html|sanitization