The Guardian has an article discussing the role of websites in encouraging "terrorists".
It states that: "Among the sites causing concern is Jihadunspun (JUS), a highly professional website which claims to present "a clear view of war on terror". It has been widely criticised in the US by agencies including the state department. "
The site Googles easily - it's at http://www.jihadunspun.com/. Apart from some really appalling poetry, it doesn't seem to me to contain any incitement to violence, just a radical leftist/islamic point of view on the "war against terror". There's probably more dangerous information on wikipedia, particularly if you look at the article history where stuff has been expunged (like here).
It strikes me as going pretty far to try and suppress sites just because they contain "thoughtcrime". The Guardian seems to be joining in this - they don't include a link to this or any sites - admittedly this one can be easily Googled, but I think that if a journalist bases an article on a web link, they should tell us what it is so we can make up our own minds.