I am really excited that you are working on this. I began working on an app extremely similar to this (down to the Twitter/IRC like notation) due to my own frustration with the inefficiency of taking meeting notes. I never finished the prototype, but I'll share my ideas that I felt were important:

* Make integration with outside parties easy (i.e. Don't force everyone in the meeting to use the app to get the benefits.) Allow me to add aliases to meeting member's e-mail addresses (i.e. @joe = joe@example.com) Allow me to e-mail a link to the minutes when the meeting is over to all parties.

* Scheduling

I should be able to send calendar invites to participants of previous meetings / define recurring meetings. If I open up the app it should know what meeting I am in by my schedule.

* Continuity

Many of my meetings are recurring meetings. At today's meeting, I want to review the open/closed items from the previous meeting. Though I still want a way to delineate what happened in today's meeting.

* Self-hostable option

For legal / contractual / paranoia reasons, I may need to keep my data in-house. For several of the groups in my company, a cloud-hosted app is a deal breaker.

* Plugins

I should be able to integrate the user directory with my company's LDAP server. I should be able to promote tasks to real tickets in my project management software. I should be able to reference items from other meetings.

Anyway, good luck with your app!