Axel Douchez, the chief executive of Deezer, announced the new features at the London Web Summit today, half a year after the service went live in Britain.
The new Deezer offline mode allows users with the Google Chrome browser to listen to their music and playlists even when they have no internet connection.
Deezer said that "unlike other streaming services", the Deezer Chrome app allows people to download as many tracks as they want, only limited to their device storage capacity.
The company has also announced an update to its iPad app, bringing improvements to the login process, new sharing abilities via Facebook and an instant converter function.
Deezer has utilised new web standard HTML5 in its latest update, in the anticipation that all mobile apps will shift to the technology in future. Adopting HTML5 also streamlines the firm's development across multiple platforms.
Following the full integration of Deezer with Facebook last September, the service is also now fully meshed with Twitter, allowing users to tweet about the music they are enjoying via the sharing functions.
Last.FM users can also click through to listen to tracks in Deezer via the website, while the new Peer Perks system offers users a three-month free trial of a Deezer subscription if they promote the site on Facebook and Twitter.
Alongside partnerships with the social networks, Deezer has been boosted in its fight against Spotify, the Rhapsody-owned Napster and We7 by teaming up with mobile giant Orange. The tie-up involves Deezer being offered to Orange customers and featuring in the firm's television ads.
Deezer has also been nominated for a Music Week Award in the category 'Non-Retail Digital Music Service'.
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Deezer managing director of UK and Ireland Mark Foster said: "We are extremely proud of how far we've come in such a short space of time.
"We've had tremendous support from both industry and media - mainly due to our music-discovery led, ease-of-access approach and our partnerships with Facebook and Orange, which are helping us drive traffic and rapid sign-ups.
"Deezer is well and truly on the map in the UK and it's fantastic to see our achievements recognised with a Music Week Award nomination."
Daniel Marhely, who founded Deezer in 2006, added: "When I created Deezer, my initial intuition was to free the music from devices. With the new functionalities of HTML5, we can actually achieve it.
"I am really excited to be running a service where innovation can be offered to users every day without having to request them to download a new version. It is no surprise that game developers have understood this and are now moving toward HTML5."
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