Online music service Spotify is hoping to launch a mobile version and expand to the US by the end of the year.

在线音乐服务Spotify希望开拓移动市场版本，并在年底将服务扩大到美国。

Spotify has gained more than a million UK users since it launched in October

The streaming service（串流服务）, which lets fans listen to more than three million tracks legally and for free, has gained more than a million users in the UK.

Speaking about the plan to go mobile, Spotify founder¹ Daniel Ek said: "We want to be everywhere. We won't only do one device."

But fans would have to pay to put Spotify in their pockets, he revealed.

The web-based service is currently free to users who accept adverts²（注意，留言） between their songs. A subscription³（捐献，定金） option, which costs £9.99 a month in the UK, banishes⁴（驱逐） the ads.

Speaking at The Great Escape music conference in Brighton, Mr Ek said the mobile offering would only be available to subscribers.

"Portability is an important aspect, [as is] interoperability（互操作性，互用性） with other devices," he said.

"That's definitely something we think is a premium⁶（额外费用，奖金） product that people are willing to pay for - being able to bring the music with you or being able to have it working on your stereo（立体声）."

The company is working on an iPhone application, but also wants to make the service available on other handsets, he said.

"I definitely hope that it will be before the end of this year that we'll do something which allows people to bring the music with them."

As well as the UK and Sweden, where Spotify was created, the current service is also available in Norway, Finland, France and Spain.

It has become a huge hit with music lovers in the UK since launching in October, but the recession and resulting advertising⁷ downturn have slowed its global expansion plans, Mr Ek said.

Sound quality

But he added: "My hope and ambition is that we'll see something at the end of the year, maybe the beginning of next year, in the US."

The 25-year-old entrepreneur（企业家） launched the company in an attempt to provide a legal alternative to unlicensed file-sharing services, where artists, record labels and music publishers do not receive royalties⁹（版税）.

He has not revealed how many users have paid to subscribe⁵. But more extras will be added to tempt⁸ people to sign up for the monthly fee, he said.

Those will include better sound quality, the ability to listen to new releases before they hit shops, more social networking features, exclusive tracks and behind-the-scenes material from big-name artists.

In other money-spinning schemes, T-shirts, concert tickets and vinyl（乙烯基） will be sold to fans as they are listening to their favourite bands.

Last.fm deal

The company is also expected to announce a deal with fellow streaming site Last.fm to provide song recommendations, making it easier for fans to find acts they like.

"We definitely want to have music recommendation," Mr Ek said. "I'd love to work with someone like Last.fm and I think in a couple of days you'll see some sort of announcement. Something will happen."

But video streams are unlikely to appear in the near future, Mr Ek said.

"It's something that we've considered but we're focusing right now on the audio side, and we're focusing on generating revenues.

"At the moment there are other features that are higher up in the priority list, but it's definitely not something that we've excluded（除外，排除）."