BOSTON -- Even for those who do not follow such affairs closely, it is no secret that radical Islam has settled a rather large piece of real estate in cyberspace. Al Qaeda and a host of other terror groups have used websites as a tool for boasting, for bloody self-promotion and, with more serious implications, to send coded signals to cells, thus commencing terror attacks. Throw the word “martyr” into Google and you will find thousands of extremist sites celebrating the lives and times of suicide bombers. With any luck, however, those days of murderous electronic mayhem may have reached...