On Thu, Feb 18, 2010 at 2:53 PM, wrote:

Thu Feb 18 05:58:09 CET 2010  Daniel Schüssler  * Monoid instance for Html  Will unfortunately break packages which already define their own instance. Possibly useful for use with things such as HoleyMonoid, though.

As far as I know, the only package which defined a Monoid instance for Html is 'haskell-ugly', and the current version of that may no longer do even that. So I don't think breakage is a concern. (The command I ran over all my local repos was 'find . -name "*.hs" -exec sh -c 'grep "instance Monoid Html where" {} && echo {}' \;') -- gwern