Digium, Top VoIP Company 2008: FierceVoIP, Fierce 15

Digium 

Where it's based: Huntsville, AL
When it was founded: 1999
Website: www.digium.com

Why it's Fierce:  Digium single-handedly defined open source telephony with Asterisk and is now almost always on the checklist for many businesses when it comes time to sit down for a discussion of IP telephony. Other open source competitors compare themselves to Asterisk and - perhaps the ultimate complement - Cisco has an internal marketing document loaded with talking points against the solution.

While it positions Asterisk as a  customizable "telephony platform" to build solutions on rather than just a vanilla IP PBX, Digium continues to steadily evolve as it hires the best and brightest programmer and developer talent as well as seasoned executives. Partnering with Skype was a Fierce move and last year's acquisition of Switchvox gave the company a needed boost in providing a flexible SMB turnkey solution for resellers.  About the only thing missing to complete its Cinderella story would be a blessing by a Fortune 500 IT powerhouse.