There might not have as many link on the web right now. Since when posting, you have to post to do follow site related to your niche too. It is easy to determine if the site is do follow. Just install SEO Quake in your browser.
You will have to find our the list of do follow forums related to your niche for good results because if you post on the different forums not related to your niches might not helpful for you and might not fulfill your desire of getting good links and increase in keywords rankings.