Last.fm, the popular social music network, has been acquired by CBS for $280 million in cash.

The UK-based music site has been around for about 5 years, and has over 15 million active users in more than 200 countries. Last.fm's leadership will remain in place and the website will retain it's separate identity.

"This move will really support us to get every track ever recorded and every music video ever made onto Last.fm," said Last.fm founding member Martin Stiksel. "With a strong partner like CBS, this is now within our reach." 

"Last.fm is one of the fastest growing online communities out there," said CBS president and CEO Leslie Moonves. "Their demographics also play perfectly to CBS's goal to attract younger viewers and listeners across our businesses."

This represents the largest Web 2.0 acquisition yet. But beyond that, this is a strong indication as to how fast things are moving lately. The lines of "distribution" are being blurred.

[BBC News via ValleyWag] 

Part two of Slacker's three prong attack on digital radio has just arrived: Slacker Desktop Radio.

Slacker Desktop Radio goes a step further than its Web-based counterpart, with features like a mini-player, visualizations, larger album art and playlists. Eventually, when the Slacker Portable gets released, Slacker Desktop Radio will sync your custom channels to the device.

The Slacker Portable, Slacker Desktop Radio, and Slacker web-app will all work together, updating each other with your custom preferences as you move from one to the other.

There's a couple downsides of course, one being that the application is still in beta and as such is pretty temperamental (I had trouble running it at the time of writing this). Also there's no iTunes integration and no support for the Mac (yet). But it's still very early, so hopefully all of that will change.

Once the Slacker Portable, their Premium Radio service and the Slacker Satellite Car Kit is available, many people may be singing an entirely different tune.

[Slacker Desktop Radio via TechCrunch] 

A recent Bridge Ratings study took a look at the competitive media landscape and the usage of the U.S. population. The results are pretty interesting...

The survey found that about 450,000 people say they listen to HD Radio daily.

Now, 57 million Americans listen to some form of Internet radio in a typical week, according to the study. Compare this to Sirius and XM, who combined pull in nearly 15 million subscribers.

Still, terrestrial radio continues to dominate, and MP3 players also hold a massive amount of earshare. An amazing 280 million Americans listen to terrestrial radio in an average week. While MP3 players - yes, including the iPod - reach 90 million Americans.

So let's break this down in percentages:

• HD Radio: 0.0015% of the U.S. population
  
• Satellite Radio: 4.8% of the U.S. population
• Internet Radio: 21% of the U.S. population
• MP3 Players: 30.4% of the U.S. population
• Terrestrial Radio: 93.7% of the U.S. population

[Bridge Ratings]

Pandora, the popular recommendation-driven Internet radio site, has said they are looking to move beyond the PC... and strike a partnership to include the service in portable devices.

Hidden in an article written about Slacker, Pandora founder Tim Westergren said that they are seeking a mobile device relationship. Slacker will bring similar music discovery functionality like Pandora's to the mobile world with its own portable media player this Summer.

Cutting the chord between Internet radio and the PC is vital to the business, Westergren said.

"It's definitely holding us back and we're not sitting idly by," he says. "Our intention is to make radio, period, and to be radio with a capital R you have to be everywhere, you can't just be on the PC."

This is getting interesting.

[MP3.com]