Our iPad app lets you view Dropbox docs or browse the web together with others in real time, while you have voice conversation (VoIP built in). There are many use-cases and we're struggling with defining a clear message around them.
(The app can be found at getjuntoo.com)
I'd suggest:
1. Looking at different industry verticals where a truly synchronized viewing of documents is of use
2. Then arrange those in a descending order using a mix of variables such as size of market, perception of pain felt by client, etc.
3. For the verticals that come out among the top 3-4, it might make sense to do another round of customer development interviews to validate your hypotheses around utility to customer
This could potentially point you to a small number of compelling use cases.
I'd be happy to look at (a) what use cases you currently have and (b) brainstorm/be a devil's advocate as you go through the process above.
