Late Sunday night I got back from my first-ever trip to the much-discussed South by Southwest (SXSW) conference for Film, Music, and Interactive in Austin, Texas. After seeing many friends and other folks in the business rave and tweet about this event for a few years, I felt compelled to add yet another conference badge to my collection. Overall I found it to be one of the best conferences for digital marketing that I have attended in some time. That means something, because I think I’ve been to more than a dozen different digital shows in the past 24 months alone. Over the course of the next few blog posts I plan to share some of my biggest takeaways and examples of Marketing with Meaning.

First up is an example of a start-up digital service that used meaningful marketing to make the conference better for nearly everyone involved: Foursquare. For those who haven’t heard, Foursquare is a mobile tool that allows you to “check in” at locations where you physically appear—essentially a way of broadcasting to friends that you are, say, having a coffee at Starbucks, or waiting in line at the DMV. This is the leading brand in a new category of “geo-location” services. You might call it “Geo-Twitter”—in fact, you can update your Twitter and Facebook accounts with Foursquare when you check in around town.

SXSW is a very big event for the folks at Foursquare for many reasons. It is the place where partners and customers gather to see what’s new. Investors are lurking everywhere to spy the next hot winner. And some of the earliest early adopters and trendsetters (including a few celebrities) share their latest findings with their friends at SXSW.

So it is a clear business objective to own this event in every way possible. For most companies, this means paying sponsorship dollars to put your name everywhere, employing booth babes to walk around with branded snacks, and maybe hosting a giant beer-for-all for everyone at the event. But not Foursquare. Instead, Foursquare stuck with what makes its service special, and spent most of its time and money making it more so.

Foursquare is already a killer app for conferences. It is most effective when a large group of people who know each other and want to get together are located in a pretty close environment. This is exactly what conferences are all about. So instead of calling or texting to find out where your friends and contacts are, you simply see where they have recently checked in and walk over to the conference room, bar, or restaurant where they happen to be. This even makes it easy to “run into” people who you might unable to reach via email or telephone.

This is why Foursquare became so popular at SXSW in 2009. So the business decided to do more with this hyper-engaged, ultra-important audience in 2010. When we got off the plane in Austin and checked into the airport, we noticed that Foursquare had created special new features for SXSW participants. The main add was a set of special “badges” that you could unlock by performing various check-ins during the six-day event. Badges are a key element of the basic Foursquare service—providing you a fun way to show that you have, say, checked in at 50 different total places or from five airports or from a boat. They are fun for the user, and cleverly (and cheaply) train people to make Foursquare check-ins a habit. Some of the special SXSW badges include the “Austin Explorer” for hitting five locations in the city, and the “Hookup” for checking in at two different hotels. For me and our team, we found that these badges turned Foursquare into a living game that made some of the boring moments between sessions and meetings much more tolerable.

Foursquare did more than virtual badges, though. The firm partnered with specific locations such as the Pepsi Refresh Cafe and SXSW Web Awards to give people temporary tattoos to match their unlocked badges. And it partnered with PayPal to donate $.25 for every check-in to Haitian relief efforts. Foursquare even reported a running total of how much you had earned for Haiti. (I believe I hit more than $8.)

Only the folks at Foursquare know how much this modest expense in programming time delivered for its business at this big event. One key data point reported on its site shows that there were more than 15,000 badges awarded, including 6,025 versions of the Austin Explorer. That means that roughly 50% of the 12,000 people who went to the Interactive conference tried Foursquare.  According to this article, there were 300,000 check-ins in Austin during the event, and Foursquare added 100,000 users overall – “likely as a result of check-ins being broadcast to Twitter and Facebook.” This might have even helped the nascent company establish a business model; TechCrunch made the case that Foursquare could create a business around building similar special apps for other conferences.

So many thanks to Foursquare for helping me get a more out of my company’s significant time and money investment in sending me to SXSW. I will certainly repay the favor by giving this new service major attention in the months ahead.