Social networking and mobile marketing have become every bit as synonymous and complementary as bread and butter.

Social networking platforms like Twitter, Facebook, and Myspace and have exploded in ubiquity and popularity in recent years with no signs of a pop cultural pullback. As a result, a recent Informa report suggested that mobile social networking in the US will see revenues ballooning beyond $400 million this year, with the mobile social networking market earning revenue in excess of $1 billion by 2013.

On the path to new heights for both social networking and mobile marketing, however, Twitter is quickly emerging as the surprising leader of the pack. Having now officially rolled out its long-hyped advertising solution, Twitter is finally graduating from a pure digital phenomenon to a pure digital phenomenon with a business plan – and one that could ultimately benefit the mobile marketing community like few ever anticipated.

Called “Promoted Tweets,” the endeavor provides for featured ads to display when users hunt for particular keywords related to paid advertiser campaigns. Later, according to the New York Times and its coverage of “Promoted Tweets,” Twitter will show promoted posts in the stream of Twitter posts – a scenario based on “how relevant they might be to a particular user.” The aforementioned Twitter stream will be rooted in such metrics as geographic location or shared interests among followers, factors that will invaluably contribute to advertisers reaching targeted consumer segments.

Twitter COO Dick Costolo says Starbucks, Best Buy, Virgin America and Bravo are already on board with “Promoted Tweets.” The idea behind the venture, adds Costoloo, is that “we want to enhance the communications that companies are already having with customers on Twitter.”

A far more intricate and potentially effectual program than many advertisers may initially acknowledge, Twitter is clearly making steps like no other in the mobile social space to bridge the remaining gaps between mobile marketing and social networking.