Re: Activities vs. Forums ?
Erich, I replied to your ticket on Trac about this, but thought I’d post my response here as well.
In practice, Forums are for focused discussion. Forum posts are not threaded and you must visit the actual forum post to reply.
Activity updates are freeform and have no real structure, but are threaded and can be replied to without having to visit the actual activity permalink.
However, I’m guessing (like you) that most people will reply to activity comments, instead of the forum topic.
The creation of activity comments have made the forums component somewhat less relevant now.
This is kind of related to a ticket I opened about the usability factor of having too many ways to communicate:
