I recently wrote about Wondershare PDF to Word online, which is a good route to edit PDF files. However, it does require the intermediate step of converting to Word. Wondershare PDF Editor includes all the features people need to manage and edit PDF files: view PDF file; edit text, object, images; annotate PDF with shapes, odd geometry, sticky note, highlighter, pencil, etc.
If you working on some project or presentation and what to share the work with your fellow buddy that very second for some corrects or proofreading, then what you do? Springnote is web 2.0 service which makes real-time collaboration on office documents and notes easy, here other users can comment, and add content as needed.