News that Vevo and Warner Music Group are the two most popular channels on YouTube isn’t strictly news – comScore stats have shown that for a while now. However, Nielsen has begun conducting its own measurements of streaming videos on YouTube’s partner channels. The company claims Vevo attracted 41.4m unique US viewers on YouTube in May, and that they watched just under 695k videos. WMG’s channel, meanwhile, attracted 22.9m uniques watching 173k streams. Interestingly, Nielsen’s numbers are less than comScore’s – it claimed 47.6m uniques for Vevo in May and 27.7m for WMG.