How can you measure the success or failure of a retail service establishment like a gym? You can look at membership numbers, utilization, earnings - as well as long-term trends in all of the above. But lately, fitness chain executives are tracking an increasingly mmm metric: Facebook check-ins. aka the "We're Here Count".

When looking at check-ins across Facebook (claimed) 1.15 billion active users, gyms (along with some chain restaurants and movie theaters - but that’s a topic for another time) lead the pack.

Why do they lead? No one has studied this yet, but we’re guessing that people like to broadcast the good things in their lives - the food they eat, the good times they’re having with friends, and, in this case, the healthy lifestyle they lead. It’s a form of social peacocking, in short.

So who’s winning the gym check-in war? That would be 24-hour Fitness with 23.9 million instances. Planet Fitness trails in second place with 18.34 million, with LA Fitness a close third at 17.77 million.

Why should you care?

Check-in counts provide some interesting - and important - insights into traffic patterns and consumers’ intent. If someone is checking in to a business, chances are that means they went there as a destination, as opposed to someone simply passing through. The act of saying “I’m here” not only requires a moment of intent, it also is intended to announce the event to one’s friends and followers on Facebook. It’s also almost always a positive event - it’s not a review, just a way of saying “I am at this place, please take notice.”

In short, it’s an incredibly valuable, trackable, and free source of advertising for the brand.

It’s no secret that marketers are increasingly turning to social media as a way to advertise and promote business. One check-in by an individual seen by hundreds of friends translates into immediate brand awareness, creates curiosity, and it also means that that particular customer is already converted (they’re already in the gym working out).

One check-in by an individual seen by hundreds of friends translates into immediate brand awareness, creates curiosity, and it also means that that particular customer is already converted.

Even more important, social marketers are turning to micro-influencers rather than those with huge followings. They’re finding that, while a super celeb may have millions of followers, the products that they endorse are often drowned out by a tsunami of reflexive likes and attention grabbing.

Micro influencers - those with under 10,000 followers - show higher engagement and conversion by those who follow them. In short, they inspire closer attention in those they’re close to.

And most valuable of all social promotions: ones that are done organically. A gym can pay for tens of thousands of ads, but 99 percent will be totally ignored. But a single gym check-in is not only seen by hundreds of your friends - it's seen as a social media post, not as an ad.

That post could inspire your friends to get off the couch and go work out at said gym.

So, for now, hats off to 24-Hour Fitness. Let the gym check-in wars begin!