Rapleaf doesn't do social. They are great at demographics. FullContact provides publicly available social profile URLs. Depends on what you are looking for.
Rapleaf was crawling and providing information crawled from social networking sites (much more than just links to profiles) back in 2007. They were providing an API to access this data in 2008 or 2009 I think. They no longer do any of this I think and have pivoted towards offline data, but don't quote me on that.