According to a report just relased by comScore, online video viewership has seen a bit of a shakeup due to relative newcomerVevo.

Launched in December 2009, the music/online video service is fed content from Sony, Universal and Abu Dhabi Media Company, with Warner considering putting content on the site. It was created to deal with the growing competition between online and traditional video in the music space. YouTube powers the video technology.

In April 2010, one in four videos online video watchers were looking at content from Vevo. That’s 43.6 million viewers, all told.

Vevo content includes videos from Lady Gaga, Justin Beiber, Beyonce and scores of other stars popular in the online video scene.

Altogether, April viewers watched around 30 billion videos, about 13 billion (or 42%) of which were hosted on Google properties, including YouTube. By comparison, other sites such as Hulu and network TV sites were left in the dust. No sites other than YouTube even cleared the 1 billion video mark, although Hulu came close.

Of the Internet’s 178 million video watchers, we collectively watched around 171 videos each in April. Other, non-comScore data suggests we watch around 2 minutes of each clip we click; we can extrapolate that viewers spent around five and a half hours each watching videos online in April. That’s about 11 minutes a day, give or take.

Do these numbers sound about right to you? Have you found yourself watching more music videos online lately?