This week, the Universal Music Group sued two video sharing sites, Bolt.com and Grouper for copyright violations, claiming that the sites allowed users to view and upload pirated versions of music videos and other content from its artists. Universal, who's roster includes such notable acts as Mary J. Blige and U2, stresses that these sites can face up to $150,000 per copyright infraction, which could add up to millions of dollars in damages.

Universal released a statement Tuesday regarding the reasons for their lawsuit. "Grouper and Bolt... cannot reasonably expect to build their business on the backs of our content and the hard work of our artists and songwriters without permission and without compensating the content creators," a spokesperson told Reuters.

Though the affected sites have not made any statements to the press, Bolt.com posted a message on their website today:

We have been notified today that Universal Music has filed a lawsuit against Bolt because our members upload videos which may contain their musicians' copyrighted videos.

We understand the love you have for your favorite musical artists, but Bolt respects the rights of copyright owners such as Universal Music and their artists, and we ask that you please do so as well by not uploading their videos to Bolt.

You can still watch your favorite music videos by visiting your favorite bands websites. Bear with us - we hope to sort this out soon!

Bolt and Grouper are small players in a growing Internet video sharing market. The market leader YouTube, a virtual unknown a year ago, was recently acquired by Google for 1.5 billion dollars in cash and stock. Other players have jumped into the viral video market as well. The social networking site MySpace provides platforms for users to share videos joining Google, AOL, Yahoo, and MSN who offer similar services.

Though a majority of videos on the web are merely short movies or clips sent among friends, and do not contain copyrighted content, YouTube has rapidly become a destination for music fans to watch and share videos from their favorite artists. It is common now for some music videos to get more spins on the Internet than on MTV. The Chicago pop-rock outfit OK Go posted an independent music video on YouTube which garnered over 2 million views. The popularity of the video garnered the band a spot on the MTV Video Music Awards as well as increased album sales. In addition to watching videos on their sites, most video sharing sites allow users to post movies on their blogs, MySpace accounts, or web pages.