NEW YORK-- Al Qaeda-linked terror groups and their sympathizers have in recent months made a big splash on the Internet, making it their communications channel of choice.
They're benefiting from free discussion boards, e-mail accounts, and other online forums for propaganda, recruitment, fund-raising, and even planning.
If law enforcement has done little to squelch these outlets, it's only in part because of the difficulty of catching moving targets. They can also provide investigators with crucial leads.
"It's a more effective strategy to actually use these sites for gathering intelligence rather than engaging in a futile effort to shut them down," said Michael Vatis, former cyber-security director at the FBI.
When such sites do get shut down, it's generally the work of hackers or the Web hosting companies that unwittingly allow them to publish, said Gabriel Weimann, who studies terrorism online at the US Institute of Peace.
In recent weeks, sites carrying gruesome images and video of beheaded Americans quickly went offline. But it doesn't take long for word to spread through chat rooms and discussion boards about new locations.