The new service is direct competition for Apple's iTunes store. Music purchased from iTunes is usually sold in the less versatile (but possibly higher quality) ACC or m4a format and comes with proprietary digital locks that limit which devices the track can be loaded on to.
Napster, the company that started the MP3 download revolution, has most recently opperated as a streaming subscription service. That service will continue.
The Napster MP3 store isn't available in Canada. I could only access it through a web proxy to www.napster.com/store. No word on when the Canadian store will be launched. It took iTunes a year and half after the US store was lauched to get the Canadian store going. It took eMusic about 5 years to get their .ca happening.