Alibaba.com

HQ: Hangzhou, China
Business: B2B e-commerce
Founded: 1999
2007 revenue: $316.3 million
CEO: David Wei

Alibaba's three Web sites—Alibaba.com, Alibaba.com.cn, and Alibaba.co.jp—connect 36 million importers and exporters from around the world. It's like a global eBay for businesses where just about anything can be bought or sold.