Naturally, neither al Qaeda nor any security organizations will discuss this openly. But it is known that intelligence agencies constantly advise against shutting down the pro-terrorism websites, especially those with message boards. It is possible to monitor who uses these websites, and it's gotten out that many active terrorists have been caught because of information obtained from monitoring who visits and uses pro-terrorist websites.
Al Qaeda has issued warnings to jihadis on the web to be careful what they say and to be aware that when they visit a website, the computer they are using can be tracked. Most visitors are unaware of these warnings or ignore them. Core al Qaeda operatives know to avoid revealing themselves so easily, but there are so many volunteers and helpers who are sloppy that the careful terrorist operatives are constantly put in danger of getting caught.
For recruiting, al Qaeda relies on people it knows to get some face time with promising prospects and check their references. This puts the pressure on intelligence agencies to create "legends" (believable backgrounds), if they want to keep an Internet persona active. Legends are expensive to create and maintain, but apparently a few of them have been used to smoke out more senior Islamic terrorists.
Most of the Islamic radicals encountered on the web are posers and wannabes. But some are serious, and there's always a risk that some of the many you write off as harmless turn out not to be. What is scary is the large number of young Muslims who see themselves as victims of Western aggression. Playing the victim is one thing, but many of these kids spout a vile message of hate and aggression. Among many young Muslims, it's become fashionable to either agree with this bile or at least tolerate it.
A lot of young Muslims don't go along with all the jihadi fantasies, and they are often the intel agents cruising the terrorist websites, looking for information and potential terrorists. When the current outburst of Islamic terrorism has run its course, there will be opportunities to reveal more details of the hidden war that was played out on the Internet, and how important it was to keep the terrorists impotent.
James F Dunnigan