Al-Qaida and its supporters have used the Internet to disseminate a wide array of new media, including video games, rap videos and comic books to project an image of "jihadi cool" and attract young, tech-savvy supporters, said the report released by CSIS in February.

"YouTube videos and online chatrooms now help disseminate (al-Qaida's) ideology to far-flung audiences, thus reducing the importance of in-person interaction as a driver of radicalization," said the report. "This development only adds to the diffusion and complexity of global Islamist terrorism: Policymakers must now counter extremism in virtual, rather than merely physical, realms."

A Facebook page titled "We Are All Usama Bin Laden" was created on the site hours after President Barack Obama announced the al-Qaida chief's death, said the SITE Intelligence Group. The page attracted more than 10,000 supporters in less than 24 hours, it said, but appears to have been removed since then.

Hundreds have also expressed support for bin Laden on the main al-Qaida website currently in operation, Al-Shumoukh.

"You lived as a hero and died as a martyr," wrote one user, identified as Ibnat Shumoukh al-Islam.

Al-Qaida has also made strides in covering its tracks online. Al-Fajr published at least two issues of an electronic magazine called "Technical Mujahid" in 2006 and 2007 that outlined how to encrypt files and hide messages in images. The magazine advocated using encryption software written by jihadists called "The Mujahideen Secrets."

Bin Laden pursued another strategy to avoid detection while living for at least five years in Abbottabad, the Pakistani army town where he was eventually killed by US Navy SEALs. His compound didn't have a phone line or Internet connection, and he relied on a pair of trusted couriers to feed him information and disseminate his messages and e-mails on small flash memory drives, US officials have said.

The al-Qaida chief was taken out despite his caution, but his army of online supporters will be much harder to eradicate.

"The Internet is proving to be the ultimate safe haven," said Brachman.