unfortunately including your link in facebook will only succeed to increase web traffic to your site but not increase your page rank... as most social sites have no follow tags.....though there are some that do follow.. here is a list
http://www.affiliatemarketingdiary.com/web-20/top-23-do-follow-social-bookmarking-sites/75/
also.. seeing htat your aim is to increase backlinks to your site.. download
seo quake... it is a browser plugin for IE or firefox.. it has a option to show which sites have dofollow tags and sites which have nofollow tags.. highly recommended for building your page rank and search engine ranking position
here is the link
http://www.seoquake.com
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