The World Economic Forum announced today it has named 39 companies as Technology Pioneers of 2008.

Among the 23 based in the U.S. are two local companies: Kirkland-based Clearwire and Seattle-based Medio Systems.

The list was narrowed down from 273 nominees. To be selected, the World Economic Forum said, the company must be "involved in the development of life-changing technology innovation and have the potential for long-term impact on business and society."

Previous winners include Business Objects, Cambridge Silicon Radio, Corel, Encore Software, Google, Mozilla and Napster.

The Forum said Clearwire, founded by Craig McCaw, "clearly has tomorrow in mind." The company is building a high-speed wireless broadband network in the U.S. and in several markets abroad.

As for Medio Systems, run by Brian Lent, the forum said: "Medio Systems is the leading provider of mobile search and advertising solutions that help mobile operators implement the best customer experience and allow advertisers to reach their intended target audiences."

A complete list of winners can be found here.