Katie Couric's Notebook: Egypt

"The people have ousted the regime."

That simple chant rang through Tahrir Square today when Egyptian protesters learned that, after three decades in power, President Hosni Mubarak was finally stepping down.

The mood on the streets quickly turned from anger and disappointment to utter jubilation.

It's hard not to share in their excitement.

When I was in Egypt, just over a week ago, the standoff was terrifying. Dozens of protesters had already been killed and a peaceful resolution was hard to imagine.

So what comes next? That's still an open question. Egypt's military has vowed to help guide the transition toward democracy rather than fill the void itself.

Wael Ghonim, the Google executive who organized what he calls Revolution 2.0, recently sent a three-word tweet. "Welcome Back Egypt." Thirty years of history rewritten in just 18 days.

That's a page from my notebook.

I'm Katie Couric, CBS News.