I've noticed that too, although it is meant to be a work tool, and I really shouldn't be spending all day reading through the best of NAAFI.
I can justify being on ARRSE as the 'Outside the Wire' is giving me some good tips on my impending civvyism, but imagebeaver.com... I'd have to get Mrs BLiar to defend me on that one, as my right to freedom of expression should be extended to boobie pics, possibly.
If you can justify some of the sites that you want unblocked, then you could always call DCSA and get them to change the permissions. And if you get them to allow us to sign onto MSN/Yahoo etc, all the best.