While waiting to the economics stackexchange to become as active as the mathematics one (and of course, meanwhile participating in it to promote its growth! the stackexchange format really seems to me to be an excellent way to organize discussion), I'm looking to see if there are other active online communities centered around economics as a scientific discipline. Does anyone have suggestions?
Have a look at these earlier questions and their answers:
You can check out the below mentioned Piazza discussion forum which is primarily for students who wish to pursue or are pursuing Masters/PhD in Economics.
There is one forum called thegradcafe, and you can easily find it on Google. I'd been its' member for a year, and there was for sure a sub-forum dedicated to economics. It still is there, but I have no idea if it's still active. Also, there are a few amazing subreddits, where you can have interesting discussions with members.