Because of the way the Skype network works (its a p2p mesh system), depending on whether the client elects to be a leaf, a node or a super node will depend on the amount of network activity you see.
The protocol was *really* not designed for mobile devices, and we are starting to see how badly it can treat the battery. There isn't much room to expand it to use push notifications either.
odd, when we were working with cell we went straight to matrix vision and they LOANED us the hardware for about a year.. Nothing sleazy at all. IBM Also loaned us a server, as did Sony (a beautiful rack-mount job which will never see the light of day).
Bottom Line - the PPC part of the Cell is rubbish, terrible IO and generally 'weak' by todays standards, the SPEs are great, but not enough memory on them (256k) for the algorithms + tables we needed to process the data.
In the end optimizing for intel & SSE3 and making the algorithms multi-core capable was less pain:performance ratio than working on the Cell which would have required all the additional work of managing DMA to/from the meagre memory on the SPE.
If it's worth doing, it's worth doing for money.