AnnoCPAN might be a great idea, however it doesn't appear to feed back any annotations to the module authors, indeed it has a big block at the top saying:

Is AnnCPAN a substitute for proper bug reports? No. If you want a bug to be fixed, or you would like a change in the official master copy of document, please follow the proper channels.

So don't rely on it getting back into the documentation of the module, and don't rely on it not becoming outdated when some bad module author goes and changes the whole documentation under its feet.

The best way to get a change to the documentation of any module I maintain is to send me a unified diff against the current version.

/J\