This small extension reduces overall size of all html documents which are send to customer's browser. It can save about 10 - 15% of original file size by removing all unnecessary comments, whitespaces and new lines from documents. As a result you'll get some performance boost - how it will work in your case? Please share the result in comments.
Stable (tested with 126.96.36.199 and above till 188.8.131.52). Can be disabled for development purposes in at System -> Configuration -> Developer (under 'Advanced' tab) -> HTML Settings.