This is planned for later this year. Need to complete a few more big ticket items. Thanks for taking the time to vote!Jonathan Fu commented
I am looking forward to this feature. Any update as to when this will be implemented?
High-level requirements gathering has begun. Please feel free to contact me (bking at ppmroadmap dot com) if you have more to add or would like to schedule a brief call to discuss. Thanks!
In development and scheduled for November 2015
We are evaluating the best way to incorporate 3rd party collaboration — e.g. comments in Basecamp and other (future) integrations — in Roadmap. We do not want to reinvent the collaboration already provided by other apps.