Electronics retailer Best Buy has seen good results via an iPhone campaign it did targeting consumers listening to music on Pandora's application for the smartphone.

Pandora claims accelerated user registrations, which have doubled since the launch of its iPhone application on July 11. Best Buy advertised within the application with a sponsorship screen and lay-over ads that brought consumers to the retailer's landing page without stopping the music experience. The ads averaged 2.5 percent to 3 percent click-through daily.

"Best Buy really integrated into the iPhone application," said Cheryl Lucanegro, vice president of advertising sales at Pandora, Oakland, CA. "The ad was immersed and integrated into the application.

"Best Buy was able to sponsor this experience for the user without interrupting the music, meaning that even when the user clicked-through to the BestBuy landing page, the music was still on so they could shop and listen," she said.

Pandora is a personalized Internet radio and music discovery service available anytime and anywhere on the PC, in the home and on mobile devices via partnerships with AT&T, Apple and Sprint. Hewlett-Packard, Microsoft, Honda, Procter & Gamble Co. and Nike advertise on the Web site.

The Best Buy iPhone landing page was specifically created for this promotion and showcased new mobile technology available at Best Buy stores.

The Best Buy ads targeted Pandora's affluent demographic of iPhone users who are predominantly males age 36, on average.

The users skew somewhat older with a higher-than-average household income and wield greater purchasing influence among their family members and friends.

Users' high affinity for Pandora means they will spend significant time interacting with the iPhone application as well.

The launch of Pandora's iPhone application has accounted for a doubling of its former average daily growth rate, up to nearly 40,000 new registrations a day.

The current 1.5 million Pandora iPhone registered users spend an average of 75 minutes per day interacting with the application, or collectively 200,000 hours, streaming about 10 percent of the online service's music.

Becks beer brewer has now begun advertising within the iPhone app, going live Oct. 23.

"As we begin to establish a critical mass with the iPhone application, it increases the value proposition for advertisers who want to take their branding message to the most engaging mobile platform right now, which is the iPhone," Ms. Lucanegro said.

"This is exciting as it relates to our mobile strategy where we will be expanding our mobile marketing options to include other smart phone platforms," she said.

A Web-enabled version of Pandora is already available on the largest mobile networks, including 16 phone models on the AT&T network and on 17 Sprint phones.

Pandora's iPhone ad platform also has the ability to hyper-target audiences for highly relevant and personalized marketing communications, such as by gender, age, geographic location, music genre and day-part listening.

"This type of advertising is not intrusive because it brings the marketer there with the music," Ms. Lucanegro said.