Give details on who has viewed a presentation you have shared. So you know where your presentation has been shared, and for how long each person viewed it. A little like some of the features available on Doc Send or Google Docs.

When you send a link to a client it would be good to know if they've opened the presentation. And when. Oh, and how many times.

Metrics for # visits, time viewed/slide, accessed by, best slide, performance comparison to other presentations and slides (Commercial use)

Add a feature to see who of the invited people viewed the document, for how long, which slides, etc.

See who has looked at your shared presentations, and see how much time has been spent on each slide.