Slacker Radio, the on-demand music streaming service, has announced that three months after it relaunched itself, more than six million new listeners have signed up. Out that amount, 100,000 have converted to being paid subscribers. What’s more, mobile adoption is picking up as more users are listening from mobile. Slacker claims that the average listening time has increased by 25 percent.

Last February, Slacker kicked off new efforts to market itself to the public, competing with services like Pandora and Spotify for mindshare. At the time, company CEO Jim Cady said that Slacker had been building a scalable business with more than 500,000 paying subscribers and over 4 million monthly users.

Cady also made a prediction: that 2013 would be a “blockbuster” year. For all intents and purposes, it looks like so far he’s right.

In the past five months, Slacker has been busy working on its relaunch, bringing its service not only to the Web, but also tablets, smartphones, consumer electronics devices, and even cars. During the Consumer Electronics Show, the company announced partnerships with Chrysler’s UConnect Access. It also has deals with manufacturers like Ford, GM, Acura, Honda, and Tesla.

Cady said in a statement that the company is “thrilled with the results of our relaunch.” He goes on to say “with our proven business model, Slacker is the only digital music service that is gross margin positive on every listener — whether they’re ad-supported or a paid subscriber.”

The increase in mobile listeners isn’t probably all that surprising. After all, Slacker’s app comes pre-installed on every Android phone sold through Verizon, Sprint, T-Mobile, AT&T, and US Cellular. It can also be downloaded from the major mobile app stores.

Slacker has been actively marketing itself as an alternative to Pandora and Spotify, saying that it has a much bigger library. Even at its rebranding event, the company repeatedly made reference to the two services touting that they were not competitive with Slacker. To make things a bit more interesting, Slacker released this video:

Craig Rechenmacher, Slacker’s Chief Marketing Officer, told us that while the company has been around for a while, it only began marketing itself now. The reason is because the company wanted to make sure that it had the right product, content, and scalable business model.

Slacker has surely come out in force to take on its competition, something that Cady admitted his company was going to do — during the relaunch event, he said there was no reason to “pussyfoot around”.

Game on.

Photo credit: DIETER NAGL/AFP/Getty Images