On the Internet, the battle against terrorists is often a private affair. There are several loosely organized, unofficial, anti-terrorist groups out there, as well as individuals. These irregulars stalk pro-terrorist Internet users, often feeding useful information to police and intelligence agencies, but also taking action themselves. Some of the action is of questionable legality, or definitely over the line. The authorities try not to take off after the irregulars, even when anti-terrorist efforts cause collateral damage (like taking non-terrorist websites offline for a while.) But at times, the irregulars and the official spies are working at cross-purposes. Many terrorist web sites are left alone by the cops because the people using it are under observation. Most of the terrorists out there are amateurs, and can often be observed by intel agencies for extended periods, without the surveillance being discovered. So the cops don't much like it when freelancers come in and shut down the pro-terrorist web site.
The irregulars often have better technical and language skills than most intelligence agencies. This means that an irregular will often track down an Internet based terrorist that the authorities have not been able to catch up with. And that brings up the problem of institutional arrogance. Police and intelligence agencies often dismiss the irregulars, although that is changing as details of more irregular successes circulates. Some intel agencies now seek out irregulars, do a little background check, and give their tips fast track access to analysts.
While most of the irregulars are patriotic geeks, some are also former residents of the Middle East. Most of these Arabic speaking geeks are living in North America, but some are in Europe, and a few can be found in Moslem nations as well. These people, generally, would not want any contact with Western espionage agencies, but they do want to bring down the Islamic terrorists that give all Moslems a bad name. So the intel agencies simply have some of their people go into virtual geek mode, join the informal online irregular groups, and pass on what they find useful.
What the intel agencies don't like to admit is that there is a major shortage of Arabic speaking analysts with a major Internet skills. The irregulars fill this gap. Why don't the intel agencies hire these irregulars. In a few cases, this has happened. But most frequently the irregulars prefer to remain irregulars. Some could not tolerate the "top secret" atmosphere of an intel agency. Some could not pass the entry tests (for personality, security, or whatever reasons), and others already have careers they are happy with, and prefer to leave the sleuthing as a part time activity.
What this all proves is that the age of the "amateur expert" is far from over. Without these freelance Internet sleuths, a lot more terrorists would be out there planning, and carrying out, attacks.