As the article points out, "...the jihadi internet is used for many things, but not for operational planning.":
"...the idea [for an attack] is useless the moment you post it on online for all the intelligence services in the world to see.
"The posting is nevertheless interesting, first of all because it is unusually specific and shows that we cannot completely dismiss the Internet’s potential as an arena for operational brainstorming. At the same time, it illustrates the lack of military know-how of many online jihadists. In much of the forum material, there is a spectacular disconnection between intention and capability. Unfortunately, the haute couture of terrorism is prepared behind closed doors."
Prêt à porter terrorism