Dropbox

Dropbox users who store PDF files on their cloud accounts will now be able to open, edit, save and share those files directly from that source, using Adobe Acrobat and Acrobat Reader apps. It's just the first phase of a new partnership between Adobe and Dropbox.

The service is available now for Windows and Mac users. Dropbox stated:

"This means you can do more with your PDFs, wherever you are. You won't lose time waiting to get back to your computer to redline or electronically sign a contract, or add feedback to a design mock. And no more printing out a PDF, writing comments on it, scanning it, and emailing it as an attachment. Instead you'll be able to open a PDF from Dropbox and edit it using the Adobe apps, then save and share your work easily through Dropbox."

Source: Dropbox