From Groupon to Gilt Groupe, several tech startups had banner years that altered our perception of technology and its role in society. Here are a few that captured Fortune's imagination.
Nowhere but online can a company stumble upon such rapid user growth or jaw-dropping investment or buyout offers. Because while the Apples, Googles, and Oracles of the world might rule, at least as far as the bottom line is concerned, arguably much of technology's cutting-edge innovation occurs within the tiny confines of a startup's HQ. And tech giant CEOs often rely on these startups to innovate in their way large companies can't, only to snap up their products and personnel with mountains of cash.
As Fortune looks forward to another year of exhilaration and tumult in tech, we spotlight five tech startups that hit their stride in 2010.