Company name: Sonopia
Where it's based: Menlo Park, Calif.
When it was founded: 2005
Year it was a Fierce 15: 2007

Why it was a Fierce 15: The company was supposed to "democratize" the carrier-subscriber dynamic in the U.S. by allowing any individual, company or organization to launch an MVNO. Sonopia contended that users and organizations would create the most successful niche brands and affinity groups to power the next generation of MVNOs. Click here for more.

What has happened since it was awarded the Fierce 15: The company imploded in April 2008, fired all of its U.S. employees and said it was going to wait around until the U.S. MVNO market recovered. They haven't done anything since.