Mobile users are more connected to the Internet than ever. As of December 2011, ComScore estimated that there are 97.9 million smartphone users in the U.S.--nearly a third of the total population.
Almost every one of those devices can provide its location to services in which users choose to participate, allowing them to tell their friends where they are, what businesses they frequent and how those businesses perform. For example, a retail store might offer discounts to entice customers to let their friends know where they're shopping and how good the store is.
















