OK it brings traffic. But does it actually help SERP by counting as a backlink? I doubt that because googlebot would have to register on facebook and make friends in order to find and crawl the links. Am I wrong?
I believe if you leave link on your profile page it is dofollow. I'm not sure about what search engines can and can't see on Facebook, but pages do get easily indexed. At the very least, it can be a good source of traffic sometimes if you create a fan page.
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