k so there's a slight variation in size from the ones in the link I gave above but probably something similar. If they are in clusters then that sounds hazardous/suspicious.

Either that or it's a new autospamming run by a system related to a porn site. autogenerated spam results Your report does sound like a new problem to hit the network.

I did the same search (after deleting .wmv from my keyword filter) & got similar results. So it does sound like a new autospamming set up.
Also see What you should know about WMA & WMV Files