Very cool! At least for me, so much of my reading is done on my mobile devices (e.g, iPhone, iPad) that not supporting those via an app is pretty much a deal killer for me. But if I could have one place to read PDF files, saved websites (e.g., like Pocket; btw, Pocket integration would seem to make a lot of sense for Polarized) where annotations/highlights are also stored in the cloud (say, in Dropbox), and I could access this on the go on a mobile device, I would certainly use your service.