A [spectacularly dull] document about FM and accessed from the Adobe site says, correctly
Today’s customer wants to give real-time feedback on digital content, such as reporting errors in documentation and contributing new content. This requires new in-built mechanisms.
Assuming that the adjective digital applies to on-line/.html as well as .pdf, I'm genuinely intrigued to know how I can deliver this level of interaction starting from FM source. Our first happy experiments with WebHelp have been very well received, but I see no sign there of any comment-harvesting or even just note-taking options.