Hi5 Networks has announced new leadership to sustain the social networking site's growth.

Hi5.com's monthly visitors rose from 31 million to more than 56 million in the first half of 2008, which marks a 79% increase and ranks the site ahead of its competitors for its speed of growth worldwide. As those figures emerged this week, the company announced that is has hired several senior executives.

"We've experienced tremendous growth in the last year, and I'm thrilled we have assembled a world-class team to capitalize on our market position," Ramu Yalamanchi, CEO of Hi5, said in the announcement. "The depth and diversity of experience of our leadership team is a huge asset and will help take our business to the next level."

Jeff Stephens has joined as CFO to lead its finance, human resources, and administrative departments. He was senior VP of finance and administration and the corporate controller at QuinStreet, an online marketing and media company. He also served as corporate controller at Sonnet Financial.

David Kim will manage partnerships, revenue initiatives, and strategic planning as VP of business development and Strategy. He was senior VP of Harcourt Education, a division of Reed Elsevier. He has also worked with the Boston Consulting Group and Wilson Sonsini Goodrich & Rosati.

Noelia Amoedo will serve as VP of Hi5 Networks Mobile, while Ram Gudavalli, has become VP of Hi5 Networks Engineering. Michael Trigg has joined as VP of marketing, after co-founding Truviso, a real-time data analytics company. He also served as VP of marketing at Spoke, a social networking site for professionals. Adriana Gascoigne, formerly with Ogilvy PR, will serve as director of communications.

Finally, Karen Richardson, an advisor to Silver Lake Partners, former CEO of analytics and Web marketing software company Epiphany, and once a senior salesperson at Netscape Communications, will serve as chairperson of the company's board of directors. Jon Feiber, general partner at MDV-Mohr Davidow Ventures, and founders Yalamanchi and Akash Garg are also on the board.