Wasn't one of the big reasons behind the TeliaSonera vs Cogent spat a little while ago the large difference in traffic going one away across the peering agreement versus the other way and that Cogent wanted Telia to pay more for that difference?

I don't know what the ratio of data uploaded to YouTube versus downloaded is in comparison to Justin.tv or other big bandwidth heavy sites, but I would guess that Google still has to pay quite a hefty price for these peering agreements. ISPs after all don't just want more traffic across their network for the sake of it.