What are the advantages of using ProofMe over, say Dropbox + Adobe Acrobat for PDF approvals?

First of all, we love Dropbox, it was one of our first integrations! However, Dropbox + Adobe Acrobat is hardly a love story. When collaborating on a PDF in ProofMe, you get precise, contextual markup and comments just like Acrobat offers, but with real-time updates, email and in-app notifications, discussion threads, instant visibility into what everybody else is saying and the ability to link to specific comments. Best of all, unlike Acrobat, there are no files or software for the reviewers to install.