Has a feature of letting other Skype users know it is available. To those that are looking for random discussion... I'd guess this is what the "all around the world thing is going on"
One other thing, I'll bet if you check you firewall it says Tons-O-machines are trying to verify that, or trying to update his client... If he has "please update me on who is available".
Of course, this is just a guess, but I have dabbled quite a bit in H.323 and it is very chatty keeping up its end of the "connection".
One other thing, you might wanna look and see if "keep alive" or some sort is checked on... that'd do it too.