The thing with that recommended post exchanging website is that people will visit your forum, 1 out of 20 will like it and read the thread before posting, 9 out of 20 will read the thread before posting just because they want to post on subject and 10 out of 20 will post without reading the thread, just by looking at the thread's title. I would recommend you starting with some friends and populating it. Or go to forums from your niche, post a lot of posts, quality ones and place your link into your signature.