I recently started using FM after a seven-yr hiatus :) There used to be a tool called FrameView or something. I think it was a cheap solution companies could purchase for subject matter experts who don't author but are involved in the review/collaboration process.
Also, I know about some third-party apps for commenting/saving changes to PDFs. I mean ones that are much cheaper than the Acrobat suite. These would solve part of the collaboration problem, but we are hoping to review/accept review comments programmatically in similar fashion to Word. Any referrals and general tips much appreciated. Cheers, Matthew Reeves mreeves111 at gmail.com