A new study of online discussion around social music sites shows Apple’s Ping is the least-talked about among Spotify, Rdio, Blip.fm and Pandora. Of the relatively little being said about Ping, 43% is negative, 3% is mixed and 54% is positive, according to the study by Infegy, which analyzes “chatter” from millions of sites on the Web.

Infegy looked at a 10,000 post sample from the past 30 days to determine how the top music sites stacked up against each other.

A topic cloud of words from posts about Apple’s Ping.

Ping has been criticized as a half-baked social network where the real goal is to sell more songs on iTunes. An agreement with Facebook that would have made it more social fell through before the release. The service was quickly overrun with spam. All in all, it has not caught on with the fire of some of Apple’s other products, and people simply are not talking about it. “With the exception of a huge spike on the day of its release, Ping chatter has been surprisingly low,” Infegy said.

Graph of the amount of talk around social music sites.

So who do users like? The streaming site Rdio registered a distant last in terms of conversation generated, but 87% of the conversation it generated was positive despite the fact that it just launched last month and costs $4.99 per month. Rdio was founded by creators of Skype and the file-sharing service KaZaA, is integrated with Facebook, Twitter, Last.fm and iTunes.

Blip.fm, the streaming service that revolves around user-created playlists, was the most talked-about service, and 80% of the conversation was positive. Pandora, the streaming music recommendation engine, generated the second-most buzz, 81% of which was positive.

The real winner may be the free streaming service Spotify, which is integrated with Facebook and generates about as much conversation as Ping even though it is not available yet in the U.S. Spotify is available in seven European countries, but its launch in the U.S. has been delayed by legal negotiations. Spotify has faced negotiation delays but is aiming to launch in the U.S. in 2011. Conversation about Spotify was 82% positive, 14% negative and 3% mixed.

Do you use Ping or Blip.fm? Which social music sites do you prefer?