I know I like to do post exchanges from time to time, but do you feel that they're effective - in terms of driving in new members - or bringing new activity? Sometimes you can have a great post exchange, and then the other poster decides to be apart of your community for good - because they enjoy it, so what do you think? Are post exchanges effective in terms of keeping a community afloat? Or driving in new content? Or do you not care for post exchanges?