I just created a free forum called http://www.inadoo.com where you can exchange your facebook i like from your facebook pages by categories (including regional categories). I also have a section for google plus link exchange by categories and twitter followers. The website contains a system to automatically login if you are logged in with facebook. The phpbb board has also a module to be able to add your facebook public profile, twitter profile to your post. There is no nofollow. So everything will be considered as backlinks. The forum categories will change over time depending on people's need. We will also try to write articles regarding facebook i like exchange, google plus exchange and its benefits.