The Slacker customized Internet radio service is now live in Canada, but with a much different offer than in the U.S.

Slacker, if you remember, is the service that allows users to create their customized radio stations compiled automatically using the system’s recommendation technology, much like Pandora. However unlike the U.S., where the service is offered both for free and with various premium tiers, Canadian users can only use the free tier for 30 days before they have to upgrade to a paid tier—starting at US $4.

According to Slacker senior VP of strategic development Jim Rondinelli, there are several reasons for the different offer. For starters, the advertising market in Canada is not as mature as that in the U.S. and as such couldn’t support a fully fledged ad-supported free tier indefinitely. Also playing a role in the decision is that Slacker has no competitors in Canada, as its main rival Pandora is does not operate in the country.

“We have a very different landscape in Canada,” Rondinelli says. “The absence of competitors allowed us to take a different approach the marketplace, but our research convinced us we would be more likely to have success offering a fully featured service than our standard ad-supported service.”

Canada also has no compulsory webcasting license in Canada the way there is in the U.S. While Rondinelli says that was not a factor in the different pricing strategy, it is a factor keeping out other such services as Pandora.

“We won't move until the economics make sense,” says Pandora co-founder Tim Westergren. “I think the licensing entities are doing a terrible disservice to their constituents (artists) by keeping us out. It drives me up a tree.”

The Slacker service is accessible online as well as via a downloadable app for such mobile smartphones as the BlackBerry and Android devices. An iPhone version of the app is expected shortly.