Subway ranked highest on a list of brands that use social media marketing most effectively, according to consulting firm Vivaldi Partners. The study sought to measure "social currency" by the level at which customers share information about a brand, and found that Subway scored big on engagement with its 21 million Facebook followers. Google ranked second, owing to its own Google+ network, while Target came in third for its many Facebook applications tailored to customer groups such as newlyweds and tech aficionados.