Maybe .. maybe not.
It seems like retail businesses would get the best bang for their buck on social sites, like Facebook or GOOGLE+. Manufacturers .. not so much. Distributors would do well, with a focus to build their brand.
I have 2 of my retailers with a good presence on Facebook .. but have yet to see any sales from these efforts. I do believe the LIKE on a site is a sort of “Testimonial”; and, it definitely has value in SEARCH results.