Editor's note: Also see CNN Radio's report on the role social media is playing in North Africa's unrest.

(CNN) -- As in Tunisia, the protest movement in Egypt is taking advantage of social media to communicate, inform and organize.

Despite attempts to block Twitter, Facebook and other sites (the government denies it was responsible), a Facebook page devoted to Friday's planned protests had more than 80,000 followers as of 2 p.m. ET Thursday, compared with some 20,000 the previous day.

Following Twitter comments with hashtags such as #Cairo, #jan25 and #Suez generates a huge flood of tweets. There is a breathless excitement about many entries, which are mainly in Arabic, English and French, but there are also scores of rumors, much invention and plenty of hyperbole.

Sifting the wheat from the chaff, given the extraordinary volume of traffic, is a full-time job. One typically overstated entry on a Facebook page Thursday read: "Live ammunition is being fired at protesters. ... Innocent protesters who want their basic rights are being massacred." There is as much misinformation as information.

But social media can help tip off journalists about developments in places they can't get to. For example, it's been difficult (and risky) for foreign journalists to report from the city of Suez, which appears to have seen some of the worst violence of the past few days. But a steady stream of tweets and blog entries, as well as photos and cell-phone video, has provided at least some guidance on the rapidly evolving situation there. In a country the size of Egypt, even large media organizations can't be everywhere, especially when the security forces are throwing up roadblocks.

As the protests have had (so far) little formal organization, social media have become a critical tool for arranging rendezvous. One Twitter entry, for example, called for a march at 3 p.m. Thursday in Giza, a suburb of Cairo. Another on Wednesday called people to Tahrir Square in central Cairo. Of course, there is a weakness in such methods -- because the authorities can also read them, and a plethora of such rallying calls can lead to confusion.

In any case, social media may be overtaken as an organizing tool on Friday -- by Egypt's mosques. The Muslim Brotherhood, which is influential in thousands of mosques throughout the country, has called for protests after Friday prayers. But the Brotherhood is playing catch-up with a movement it has done little to influence so far.

Social media are also a source of practical advice for those on the streets. One tweeter advised people how to wash tear gas from their faces, and warned people to avoid wearing contact lenses during the protests. "Spit, blow your nose, rinse out your mouth, gargle. Do eyewash from inside to outside with your head tilted to side," the tweet said.

The sheer scale of the online "movement" -- and the speed with which it has grown -- is breathtaking. The hashtag #jan25 began "trending worldwide" on Twitter Thursday, generating dozens of tweets and retweets every minute. When Mohamed ElBaradei arrived in Cairo late Thursday, the retweets went into overdrive, complete with plenty of advice for him.

A Facebook page dedicated to the memory of a young man allegedly beaten to death by police in Alexandria -- "We Are All Khaled Said" -- has mushroomed to more than 20,000 followers. It includes cartoons, photographs and videos, as well as messages of solidarity from across the Arab world and beyond. One entry from an Algerian read: "People of the Algeria are with you" (sic).

There have been some imaginative Facebook and blog creations, too. One activist used dramatic photos of the unrest in Cairo to create online posters for Friday's planned protests, which he titled "Walk Like an Egyptian." Others have set photos and video to music, and posted reports from international TV networks. Egyptian state media have so far offered scant coverage of the protests.

In another example of how the digital age has changed everything: dozens of high-quality photos of the demonstrations have been posted on the online photo-share site Flickr -- although that's not without risk if the authorities decide to track down protest ringleaders.

Online activists -- normally young professionals and often multilingual -- have also been quick to find ways to combat the interruption of social media sites, with links to sites offering free downloads. One message read: "Nokia users in Egypt, use Snaptu application and Twitter and Facebook will never go down."

People have also used sites known as proxy servers, which allow users to surf the web almost anonymously and offer access to banned sites by circumventing the host country's servers. A similar method was used by WikiLeaks when its website was taken off Amazon's servers in the United States.

But whoever is trying to interrupt internet traffic from Egypt is having some success. On Tuesday, a broadcasting site called Ustream had a feed showing protests in central Cairo. But the stream was gone a few hours later, replaced by a message that read: "Servers unavailable -- possibly blocked in Egypt?" And whether because of the volume of traffic or efforts to hobble social media, many in Egypt were lamenting their inability to access Facebook and Twitter on Thursday.

TE Data, an internet service provider that says it provides 70% of Egypt's internet infrastructure, tweeted on Monday that it was not being shut down. But one customer said Thursday he had called the company to complain about service disruption only to be told that the servers were "undergoing repair." There were also tweets -- unconfirmed -- about the BlackBerry messenger service, BBM, being shut down.

Anonymous, a U.S.-based group also involved with the WikiLeaks cause, has lent its support to the protest movement in Egypt. Its activists run computer programs that flood designated websites with requests until they crash. On Wednesday, Anonymous activists tried unsuccessfully to disrupt the Egyptian Ministry of Communications and Information Technology site.

But it would be misleading to suggest that until this week, social media had no role in Egypt. A few bold bloggers like Kareem Amer (recently released from prison after serving a four-year sentence for "defaming the president and spreading information disruptive to public order") have long been a thorn in the side of the Mubarak government. Amer is blogging again this week from the city of Alexandria, advising the president that it's time to leave.

Strangely enough, one of the earliest hints of the power of Twitter came from Egypt. In April 2008, an American journalist, James Karl Buck, and his translator were detained while covering an anti-government protest. Buck managed to send out a one-word tweet while being taken to the police station. It said simply "arrested." Within seconds friends and followers knew of his situation and worked to get him released. Buck was able to post from jail until -- less than 24 hours later -- he was able to tweet: "free."