"you have an open platform to share and annotate scanned docs." I'd run with that! Is anyone else running with that? I mean sure you can annotate in acrobat

"you have an open platform to share and annotate scanned docs." I'd run with that! Is anyone else running with that? I mean sure you can annotate in acrobat reader (since Acrobat Reader 9), and sure you can use Flash paper + FLEX like Adobe connect and cozimo.com. But if just received a PDF as an email and I want to send back some comments/ suggest corrections what would I use? Is there a web app for that?