Pdf Collaborate lets you share PDFs with others, and work on them together.
You can use your Wacom tablet, or your devices screen to annotate the PDF live with others.
Simple add your PDF to the app, click collaborate to invite others to view it via email, then start communicating with them.
It has never been easier to share your notes.
You can download PDF Collaborate from the app store right now, for 99 cents: PDF Collaborate on iTunes
Part of the Inkathon hackathon https://inkathon.devpost.com/.