Freed opposition leader Wael Ghonim appears before hundreds of thousands of protesters in Tahrir Square

A young Google executive who helped ignite Egypt's uprising energized a cheering crowd of hundreds of thousands Tuesday with his first appearance in their midst after being released from 12 days in secret detention.

"We won't give up," he promised at one of the biggest protests yet in Cairo's Tahrir Square.

Wael Ghonim, a marketing manager who became a hero to anti-government protestors after he went missing on 27 January, confirmed in the interview following his release that he was behind a highly influential Facebook page that helped lead to what he described as "the revolution of the youth of the internet."