Vevo viewers down 20% year-to-year

Note: This story was updated to include an additional response from Vevo.
Music video platform Vevo, which had been one of the fastest growing video properties on the Internet, is witnessing a steep viewership drop, at least on the web.
According to numbers released Monday by Internet usage tracker comScore, Vevo’s unique viewers in the U.S. during May dropped 20 percent from the same period last year, from 60.4 million to around 48.3 million.
Meanwhile, the average number of minutes each viewer spent watching Vevo videos in May declined 26 percent over the same period, from 105.1 to 77.7.
The online music platform, jointly launched in December 2009 by Sony Music Entertainment, Universal Music Group and Abu Dhabi Media, had been on a meteoric rise, with unique viewers growing 44 percent from June 2010 to June 2011.
So what’s going on?
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A Vevo spokesperson told paidContent Monday that the comScore metrics don’t offer a complete picture of a content business that has migrated to some degree from a core YouTube channel to mobile platforms, areas that not included in the research group’s measurement.
Vevo claims “active” users of its mobile apps have increased 46 percent year over year, with mobile streams up 434 percent over that period, reaching 450 million worldwide in May.
Added: Vevo additionally notes that a methodology change enacted by comScore in July 2011 renders our May 2011 – May 2012 comparison of minutes spent by user moot. In fact, minutes spent by user per month watching Vevo content have actually risen since the methodology change. 
Vevo also attributes some of the discrepancy to Google’s redesign of YouTube, which has moved away from feeds of most popular videos to a channel/subscriber model.
The comScore metrics also don’t reflect performance in other territories where Vevo operates, such as Canada, the UK, Ireland, Australia and New Zealand.
Note: This story was updated to include Vevo’s response.