'Superluminal' Laser Questioned

mreece writes: "Recently on Slashdot there was a discussion about researchers who claimed to have observed superluminal propagation of a laser pulse. Three researchers from the Naval Research Laboratory, Plasma Physics Division, in Washington D.C., claim that this is not a valid interpretation, and that the propagation was not superluminal. The preprint is available in PDF format from http://arxiv.org/abs/physics/0010033. IANAP (yet), but it looks valid."