A social media marketing company called Syncapse surveyed 4,000 people who have “Liked” the top 20 brands that have pages on Facebook and figured out exactly how valuable those “fans” are.

They did what?

The study (“The Value of a Facebook Fan: An Empirical Review”) estimates that someone who has Liked a brand will spend an average of $71.84 more each year on that brand’s products or services than will someone who has not Liked it on Facebook, for a total average annualized value of $136.38.

Product spending was only one of six fan benefits that Syncapse studied. The others were loyalty, propensity to recommend, brand affinity (“perception and recall”), media value (efficiency of Facebook vs. other ways to reach consumers) and acquisition cost.

In most cases, the average fan was more valuable to the brand than the average non-fan, though results varied widely on an individual basis. For example, some fans spent no money at all on a brand and never recommend it to friends.