The Internet is increasingly being exploited by terrorist groups, who are using the medium to multiply the effectiveness of their planning, recruitment, and propaganda, says an Israeli researcher. For instance, such groups have become sophisticated enough to build sites "narrowcasted" to women and children.

Gabriel Weimann, professor of communication at the University of Haifa, Israel, has done empirical research into the evolving nature of terrorist use of the medium, which he describes in a forthcoming book, Terror on the Internet: The New Arena, the New Challenges.

Last week Google, Yahoo, Microsoft, and Cisco Systems were hauled before Congress and accused by legislators of abetting human-rights abuses in China. Weimann points to the opposite issue: the essentially unchecked use of the medium to spread violence and hate.

He argues a little censorship might not be such a bad thing. Weimann also believes some kind of a global body should advise Internet Service Providers (ISPs) on how to enforce their terms of service. While that is surely more easily said than done, his thinking at least offers a problem statement -- and a detailed glimpse into this netherworld of the Web.

Technology Review: Your research says there are now 4,800 "terrorist" websites, up from just 12 eight years ago. How do you define "terrorist" and how do you count such sites?

Gabriel Weimann: When you live in a place for many years, you know your neighbors well. I have lived in the terrorist neighborhood on the Net for years. You learn their fingerprints in terms of style, signatures, symbols, dialects. I consult those who know the language well -- the religion, the mentality, the dialects. And we refer only to terrorist organizations as listed by the U.S. Department of State.

The growth of these terrorist websites is [proportionally] faster than the wider growth of the Web. But it didn't grow up steadily. The big jumps were after September 11, and another one came after the attack on Afghanistan, and then after the war in Iraq. The biggest enemies of the United States are using American servers to do this (see "Terror's Server").

TR: Any new trends on this front? Terrorist wikis and blogs?

GW: We are now seeing "narrowcasting." Some groups are slicing up their target audience, by appealing to different audiences with different messages, styles, arguments, rhetoric. You can find terrorists that have 8, 12, 20 audiences. For example, some websites are used only to target and recruit children. Hamas is doing this, Hezbollah is doing this. They have computer game wars online that are used to attract children -- to train them, actually. And there are websites for women posted by Al Qaeda and its affiliated groups.

TR: Where are these groups getting the technological savvy -- how are they actually doing this?

GW: You really do not need much. Most of my first-year undergraduate students know how to establish a website, how to post a message, how to post movies or text. So do my children. You really need only one or two guys who can handle this quite common use of the Internet.