In the convoluted mobile payments space, there's perhaps no other company with more momentum than Square. During its latest round of funding, the three-year-old platform led by Twitter co-founder Jack Dorsey raised over $200 million and is now valued at $3.25 billion, according to AllThingsD. Those strong figures follow a blockbuster deal with Starbucks announced last month which will see the coffee giant accept payments through Square nationwide. Starbucks also kicked in a $25 million investment as part of the agreement and as such is listed among Square's major backers for this funding round.

In a press release announcing the news, Square highlighted its rapid growth over the past year; the company has grown from 150 employees to more than 400 and now processes $8 billion in annualized payments. Compare that to one year ago, when the same figure was $1 billion, and it becomes easier to visualise Square's upward swing.

A major reason behind that success has been expanded availability of the company's signature white plastic credit card reader. AT&T became Square's most recent retail partner in late August, with the device — compatible with both iOS and Android hardware — now sold at over 20,000 US locations. Its ease of use and adoption among small business have helped Square gain a foothold in consumer mindshare, something competing platforms like Google Wallet and PayPal (at least when it comes to mobile payments) have struggled with. The company has plenty of work to do if it hopes to revolutionize the payments industry, but it's certainly faring better than the competition at the moment.