It was reminiscent of Iran’s Green movement protests in 2009. Protesters flooded Cairo’s main squares and Twitter, Facebook, Youtube, and Flickr flooded the Internet with updates. Supporters of Egypt's protesters around the world spread information in updates so rapid and numerous that the collective coverage could probably be classified as viral.

Some protesters are still out in the streets and on the Web demanding greater freedom and the end of President Hosni Mubarak’s rule. The scope of the protests is "unprecedented," says former Monitor Cairo correspondent Dan Murphy. The success of Tunisia’s protests made the difference, indicating to Egyptians that maybe their protests could have some results this time around.

The Egyptian government appears to have shut down Twitter, though Egyptians still accessed the site using proxies or simply by calling friends outside the country and having them tweet for them. The #Jan25 hash tag (the designated tag for today’s protests) was catching more than 25 new tweets a minute in the middle of the day (EST) Tuesday. Many of those still seemed to be coming from Cairo and other parts of Egypt. Tweets are filled with everything from warnings of tear gas to notifications of free food being handed out to protesters.

One foreigner living in Cairo (according to his profile) wrote, "It's incredible: an ocean of ppl standing up 2 a sea of policemen. I've never seen the Egyptian ppl this empowered. Ever. #Jan25."

An Al Jazeera correspondent in Latin America re-Tweeted protest chants from protesters in Egypt: "Mubarak out, Egypt forever free" and "Rally Rally till Regime is Down!" Word also spread of alleged arrests on the streets, and one of the men reportedly arrested gave a steady stream of Arabic and English updates from Alexandria until he was stopped. Videos posted on Youtube and similar sites showed protesters tearing down the many posters of President Mubarak throughout Cairo and the rest of the country.

Throughout the day Tuesday there often wasn't enough Internet access to allow the flow of information from the streets – Twitter also included numerous requests for Cairo residents living near protest sites to unlock their wireless routers so that protesters could access the Internet.

And that was only on Twitter. Searching "protests in Egypt" turned up more than 1,000 photos on Flickr. Dozens of videos were uploaded to Youtube. Facebook remained unblocked while Twitter became more limited, and events, pages and groups filled with a steady stream of updates.

In Iran's case, the explosion of support on social media didn't translate to an achievement of the protest's goals, and an endless series of tweets from Tahrir Square are unlikely to topple Mubarak's regime by themselves. But social media reveals that many, many Egyptians hope it will happen.