I'm doing much the same thing with my forums. I use the reports section of the course (in the left hand menu) and set activity to the forum I'm interested in and the dates to all dates and the actions to add for posts and replies, and view, if I want to see how they've been reading the forum. I usually download
this as an excel spreadsheet to sort it by student.
There is also an activity report that gives you a summary for all the forums in a class.
Checking the forum posts and activity reports for each student from their profile page provides a bit more information, but requires visiting each page.
I'm not totally happy with this way of doing things. There is no way to automatically link the grade to a number of posts made. The gradebook just averages the ratings of however many posts they do. So I have to go back and add or subtract points if they do less or more posts than required. There is also no way of easily distinguishing between forums that require more posts, and should get more points, from those with less, except via each forum into a grade category and adjusting how much it is worth.
It also doesn't seem to distinguish between posts and replies as BB does.
If someone else has found a better way of doing this in Moodle. I'd be thankful.
I hope this is of some small help