With its billion-dollar acquisition of Instagram, Facebook now has a killer photo app that plugs a big hole in its mobile strategy. But it also gets something else: about a dozen talented employees who know how to create a great user experience. And that expertise will be critical to Facebook's future. Click on to meet the tiny team that built Instagram into what it is today. Notice any patterns in the backgrounds of these Instagrammers? That's no coincidence.

Role: CEO and co-founder Systrom is a self-taught coder with a background in marketing. It doesn't hurt that he boasts a slick Silicon Valley bio: He graduated with a BS in Management Science and Engineering from Stanford in 2006, interned at Odeo, then spent two years at Google working on Gmail and Google Reader and one year as product manager at travel recommendation start-up Nextstop.com. Guess who bought Nextstop in September 2010 for $2.5 million? Yep, it was Facebook. Turns out Zuckerberg has known Systrom for a while and even offered him a job back in 2004, before Facebook launched photo sharing.

Role: Co-founder and lead software engineer A fellow Stanford alum, Krieger has remained largely out of the spotlight"”not unusual for a lead engineer. But his handiwork is all over Instagram's design and development. The co-founder interned at Microsoft and graduated from Stanford in 2009 with a BS in Symbolic Systems and an MS in Human Computer Interaction. After graduation, Krieger joined the Web messenger service Meebo as an engineer and user-experience designer.

Role: Business operations Cole joined the Instagram team shortly after she received her Masters in Business Administration, Marketing, and Strategy Consulting from (you guessed it) Stanford in 2011. Cole is an important component to the team because she was the first business hire. Cole has worked at big name companies like Chrysler, Del Monte Foods, and Sephora, so she presumably knows what it takes to maintain a voice at a larger company like Facebook.

Role: Community and partnerships While Riedel doesn't boast the Stanford connection, he has had experience at both Facebook (with Zuckerberg) and Nextstop.com (with Systrom). Riedel's knowledge of the user is integral not only to Instagram, but also to Facebook. At Facebook in 2007 he gathered feedback, identified trends, and determined whether users' reports of abuse violated Facebook's Terms of Use. While these issues are different in 2011 than they were in 2007, Riedel has the right experience to tackle them again and be the bridge between Instagram and Facebook users. Already there has been a backlash about privacy concerns from Instagram users.

Role: Engineer Sweeney is the wild card of the group. With no college degree, he still managed to be the first engineer hired on to the Instagram team in 2010. Self-taught, Sweeney became serious about programming in high school and worked for a number of start-ups in Chico, California, before moving to San Francisco to work as director of development at social-marketing firm EGG HAUS. As luck would have it, Systrom rented a desk across from him in 2010 and the two built a relationship that eventually led to a job for Sweeney. Sweeney could be the troublemaker in this acquisition, though, as he told PandoDaily in a recent interview that he fears "what happens when we [Instagram] grow into a "˜big boy company.'"

Role: Community Zollman is a pro in the guerrilla-marketing aspect of social media. The proof: Instagram boasted 30 million iOS users in 18 months, generally through word-of-mouth. Is there a role for her talents at a place that needs little to no marketing? Similar to Riedel, Zollman brings an intimate knowledge of Instagram users' likes and dislikes. Before she joined the start-up, Zollman was a user support specialist at the conversational Q&A service Formspring and worked in customer relations at Linden Labs, the maker of Second Life.

Role: Community Education: BA American Studies (American Art) and Spanish from Stanford Previous experience: SFMOMA and ugallery.com

Role: Engineer Education: BS Computer Science from Stanford Previous experience: Microsoft, Google, co-founder of Modi

Role: Engineer Education: BS Computer Science from University of Tulsa Previous experience: Boxbe, soundtrckr, 8tracks, Gowalla

Dan Toffey Role: Community Education: BA Political Science from Reed College Previous experience: The office of U.S. Senator Mary Landrieu and the Commodity Futures Trading Commission. (Another Washington connection couldn't hurt Facebook.)"”Maeghan Ouimet