Sometime ago before the block, I saw some trunk traffic snapshots on the PTCL and other networks. Youtube only constituted a small amount of traffic where as Bit Torrent/Torrent traffic was the highest with Flash content but Youtube site traffic was already very low. My golden bird informs me that despite Youtube's blockage, there is no significant impact on traffic. Some suggest that people are catching up with using unblock proxy mechanisms to access youtube and a survey of Facebook reveals that most of my contacts in Pakistan still share youtube videos despite the block.
I am between airports and will post some statistics as soon as my bird gets back ;o)