We can only hope that this is the case.This could then be applied to Xen, as it is a registered trademark. There is noway Facebook can get away with that nonsense, especially when the site isn't even a social network, but a site purely for teachers to share resources, experience, knowledge, etc.
Most of those sites don't directly compete in some way against Sony however (Unless they're anti-PS3 sites), and actually do more good if they're a fan site, as theres a possibility of gaining more sales due to something said....Stupid. They shouldn't be able to copyright/trademark or even SUE over the word Book as it's a COMMON WORD. Hell, if this uses any logic at all then Sony should be suing over the use of PS3 (which is their trademark, btw) outside of their products and third-party owned licensed products, which I haven't seen happen yet. There's no sense in this at all.