Adverts are now being delivered to mobile users of Microsoft's MSN site in the US, with Paramount Pictures and Jaguar Cars North America among the first companies to advertise on MSN Mobile.

Microsoft already displays mobile ads in the UK, Belgium, France, Japan and Spain. The technology that presents the ads comes from ScreenTonic, a company which Microsoft acquired earlier this year.

Microsoft trails its biggest competitors in the PC-based online advertising market in bringing ads to mobile users, but its late start may not have any significant effect. "AOL and Yahoo have previously introduced display ads, but the mobile user base is still on the small side compared to the net, so they're not truly late," said Greg Sterling, an analyst following mobile search as part of a joint venture between Sterling Market Research and Opus Research. "It's not like there's a huge opportunity cost here or revenue lost." Google also supports ads for mobile users.

So far, it looks like the mobile environment is echoing the PC world in terms of mobile advertising market share from the search leaders, Sterling said. However, because it's such a small and changing market, any of the participants could take the lead. "It'll continue to be fluid for the foreseeable future," he said.

In addition to the new display ads, Microsoft also introduced some new features to its MSN Mobile offering. Users can now buy movie tickets on their phones through a deal that MSN Mobile has with

Users will also be able to buy ringtones, wallpaper, games and video clips on MSN Mobile via an agreement Microsoft has with Thumbplay. MSN also now offers horoscopes to mobile users.