Social media. ROI. They often seem like two pieces from two different puzzles. And for good reason: it can be hard to quantify the value delivered by a single ‘friend‘ or human interaction.

But for major brands, figuring out the ROI of a social media initiative is something that realistically has to be done if social media is to prove itself worthy of larger investment.

But there’s potentially good news for brands: social media management company Vitrue thinks it has the answer to a piece of the puzzle, namely an answer to the question “How much is a ‘fan’ on Facebook worth?

The answer: $3.60.

To get that number, Vitrue looked at data collected from its clients, which combined have over 40m fans on the world’s most popular social network. The data related to impressions generated for these brands by their presence in Facebook’s news feed. According to Vitrue’s math, 1m Facebook fans produces $3.6m in media value over the course of a year if one assumes a $5 CPM.

So is this the news brands have been waiting for? Not quite. That’s because, in my opinion, ‘media value‘ analyses are some of the most deceptive around. Instead of looking at what an initiative or campaign produces in action (sales, etc.) that clearly translates to the bottom line, media value is often an easy way for marketers to come up with a nice-looking number that seems to justify the initiative or campaign and nothing more. An ad campaign costing $2m might produce only $100,000 in sales, so determining that another campaign generated $2m in ‘media value‘ might look good on paper, but it doesn’t mean that this campaign delivered $2m of real value either.

In the sponsorship world, where the equivalent media value metric gained its popularity, its credibility is on the decline. In discussing equivalent media value in his book, Sponsorship for a Return on Investment, Guy Masterman wrote, for instance, that “the method is now being increasingly discredited, in particular by sponsors who are far from convinced of its accuracy.” One of the problems, Masterman notes, is that “in many cases, rate-card prices are used, and yet in industry, rate-card prices are seldom the final prices that are paid.

In this case, Vitrue’s $3.60 figure is based on an assumption of a $5 CPM, which any online media buyer knows is very high, especially for user generated content properties, where CPMs (and eCPMs) are usually measured in pence, not pounds.

None of this is to say, of course, that a Facebook friend isn’t potentially worth $3.60 to a brand. But if questions around social media’s true capabilities are ever going to be addressed to the satisfaction of brand marketers for the long haul, much more than ‘media value‘ is needed.