Last week, we took a look at how consumers use mobile social networks. This week, we'll look at four mobile applications, and to keep things focused we'll stick with the iPhone. One thing these apps have in common is that they were used as examples at 360i's Digital Marketing Summit last week, covered on the agency's Digital Connections blog, either during my presentation on emerging media or in roundtable discussions.  Here are how four different apps incorporate social elements.

Yelp

Here's a classic example of a site fueled by user-generated content running as a mobile application. It doesn't become any more or less social in this context; Yelp is one of the more intuitive review sites, with an active community constantly contributing. In a mobile social context, Yelp needs to make sure it's just as easy to access and write reviews and then share listings with others, and all of that can be done here.

Yelp delivers a new twist with augmented reality (read more on the subject in a column posted earlier this month). Through its Monocle feature on the latest iPhone, users can see listings appear in their surroundings as viewed through the camera. This makes the reviews more accessible, but again the social functionality isn't, well, augmented here.

Sit or Squat

Like Yelp, Sit or Squat's a user-generated content site accessible via the Web. Yet as any parent who's tried it knows, this bathroom-finding program is far more useful via mobile, and the iPhone app is especially intuitive. I've tried it for finding bathrooms, and I've even contributed one with photos (just look for the New York City Westin around 43^rd St and 8^th Ave). The overall social principle is similar to Yelp's, though: get users creating the content, and make it easy for anyone else to benefit from it.

Foursquare

It's a game, a social network, and maybe even a social experiment.  With Foursquare, users check in wherever they are (right now it's just for select North American cities) and earn points for doing so, while earning extra points for going out several times in a night or visiting new places. There are other hooks to keep users coming back. Badges are earned for completing challenges like going out four times in a night or, for New Yorkers, going out north of 59^th Street. If you visit the same place often enough, you become the Mayor, another bragging right.

Unlike the other applications mentioned, the whole point of Foursquare is the social experience: telling others where you are, seeing where your friends are, and earning more points than others in your city. There are also reviews and tips for each location, so this too fits in with the user-generated content realm.

2012

The app for the upcoming disaster movie originally wasn't social at all. The point of the app is to complete a number of survival trivia questions and complete your journey to the other side of the world. I'm horrible at it and wouldn't be inclined to share my score with my friends -- until I get some practice.

The app has since evolved. First, it incorporates Facebook Connect to share certain questions. Oddly, sharing your final score isn't an option, and I couldn't actually get Facebook Connect to work. Still, the movie's not out for a couple months and the app's already getting updated, so the studio has time to work out the few kinks. It's a terrific app and now includes multiplayer functionality, taking advantage of the latest iPhone release's social functionality.

Will all mobile be social?

Incorporating user-generated content, location-based social networking and multiplayer gaming are just some of the ways mobile apps can be social. Not all apps need to be social at their core, but it's increasingly where they're going -- just like the Web itself, where even the most traditional and driest sites are incorporating social functionality. That doesn't make all mobile media social, but the best apps in the space will incorporate what's especially social about mobile devices and create a unique experience combining those elements.