Yesterday, RealNetworks launched a Web site urging visitors to sign a petition to Apple, its principal rival in the downloadable-music business, urging the company to support the concept of making digital music from services other than its iTunes Music Store playable on its iPod music player.

The electronic petition, which sought the names and comments of visitors, was expressed as a public-spirited appeal on RealNetworks’ new “Freedom of Music Choice” site.

The Apple fans left so many angry (and sometimes obscene) comments on the petition that RealNetworks cut off visitors’ ability to post and read comments.

But someone took the 859 comments already made and posted them elsewhere .

Later, someone created a Web site containing a satirical version of RealNetworks’ message, chastising the Seattle company for “choosing a shameless stunt geared towards their own ends rather than somehow championing the consumer.” By late afternoon, 688 people had signed that petition.

The incident was the latest dust-up around Harmony, a technology from RealNetworks that allows playing tunes bought from its online-music service on a variety of devices, including the iPod. Apple, which didn’t authorize Harmony, has threatened to sue RealNetworks over it.

From Seattle PI.