Company name: Obopay
Where it's based: Redwood City, Calif.
When it was founded: 2005
Year it was a Fierce 15: 2007
Website: www.obopay.com

Why it was a Fierce 15: The company had inked deals with MVNOs Amp'd Mobile and Helio for a service that allowed users to set up stand-alone payment accounts--Obopay Prepaid MasterCard cards--that could be used to send and receive money between users or make purchases. The company charged 10 cents per transfer of funds between users, paid by the sender. Retailers were charged based on the amount of each transaction. Obopay Prepaid MasterCard cards were accepted at 24 million merchant locations and over 1.1 million ATMs around the world. Obopay also inked an impressive deal for a pilot program to allow Citi customers to send and receive money from their phones. Click here for more.

What has happened since it was awarded the Fierce 15: Obopay has established partnerships with big players such as MasterCard and Citibank. Nokia made a $70 million investment in the company in March, and its technology forms the basis of Nokia's new Nokia Money effort. Obopay also launched its Obopay Family Account, which the company said allows parents to set up accounts for their children and see where they are spending the money, among other features.