Mass merchandiser Target expanded its banner ad campaign with Pandora to promote its exclusive sale of Christina Aguilera's new CD release.

Target's media buy with mobile ad agency The Hyperfactory included banner ads on Pandora's personalized radio service iPhone application that drove consumers to a branded mobile Web page with an offer of a free Christina Aguilera ringtone. The goal was to promote the deluxe version of the pop diva's "Keeps Getting Better: A Decade of Hits."

"Target wanted to reach teenage girls to promote the new Christina Aguilera album, and we were able to target that demographic," said Chris Negron, central vice president of sales for Pandora, Oakland, CA. "Target was very pleased with the results and we actually have some other things cooking with those guys."

When iPhone consumers clicked on the banner ad, they were redirected to http://www.bmobilehost.com/christinaaguilera.

This was Pandora's first partnership with The Hyperfactory.

In less than five months, Pandora has reached the milestone of 2 million downloads from the App Store, making it one of the most downloaded free applications on the Apple iPhone.

Pandora was included in Apple's rollout of a Top Apps category on Dec. 1 in its new year-end section on the iTunes store.

In the free application category that showcases the most downloaded applications of 2008, Pandora took the top spot.

The first advertisers to launch on Pandora's iPhone application were Best Buy and Beck's, followed by other brands such as Microsoft, Honda, Procter & Gamble, Hewlett-Packard, Nike, Kraft Foods and Target.

Target's banner ad campaign on Pandora's iPhone application ran Nov. 9-22.

Ms. Aguilera's "Keeps Getting Better: A Decade of Hits" was released Nov. 11.

Target ran a TV commercial to promote the release of the CD.

Target also placed banner ads on 310.tv, a new mobile blogosphere platform, to promote Christina Aguilera's new CD release.

In addition to the headers and footers, Target's media buy with Snakk Media on 310.tv included a sponsorship and run of site, or ROS (see story).

Ms. Aguilera scored her first hit single, "Genie in a Bottle," in 1999. The song reached No. 1 on the pop charts.

For mobile marketers, Pandora's iPhone application is a platform to reach what many believe to be the most engaged and affluent mobile consumers nationwide.

Pandora's targeting capabilities offer a way for brands to finely tune their ad messages to a defined audience.

Pandora can target by age, gender and ZIP code and will implement targeting by musical genre in the near future.

The 2-million-application milestone means that Pandora reaches roughly one in every five iPhone users nationwide.

The launch of Pandora's iPhone application accounts for one-third of all new users since July, and has significantly accelerated the growth of Pandora's registered user base, on track to reach 20 million before the year's end.

To date, Pandora claims that its iPhone ad platform has delivered more than twice the response rates compared to its other ad products due to the highly interactive nature of the device.

Additionally, iPhone users can continue to stream music while they engage with the ad, so the user experience is not diminished.

Currently, Pandora's iPhone users spend an average of 90 minutes a day interacting with the application, accounting for nearly 1.2 million ad impressions per day. Their average age is 34 and three-quarters of them are male.

Pandora is a personalized Internet radio and music discovery service available on the PC and on mobile devices via partnerships with AT&T, Apple and Sprint.

Pandora is based on the Music Genome Project, an analysis of popular music.

Each song in Pandora's collection is analyzed by more than 30 trained musicians and assessed against nearly 400 distinct musical attributes such as melody, harmony and rhythm to capture its unique musical identity.

Using this information to build playlists based on musical similarity, listeners can simply enter a favorite song or artist and launch a personalized listening experience that includes discovery of new bands, artists and songs.

Pandora claims to be the largest online music site based on monthly unique visitors, with a growing user base of more than 19 million registered listeners and a database of more than 575,000 songs.

Pandora is completely ad-supported, meaning it is free to the consumer and monetized based on advertising.

For the first couple of months, the iPhone was a sponsorship model, meaning marketers got exclusive branding of the iPhone experience.

As the audience has grown, Pandora now offers CPM models, which allows multiple advertisers. Now advertising on the iPhone is overlay that is clickable, per the company.

Advertisers can choose whatever they want to market on the destination page. The destination page can be any URL.

Also, Pandora offers click-to-call on the destination page for a follow up offer or information. The destination page can play YouTube video.

The Pandora music service is available on 18 Sprint phones and 16 AT&T phones, including the iPhone.

For the time being, mobile advertising is only available on the iPhone, with other smartphones launching soon.

"Pandora is committed to providing content users value and integrate into their lifestyle," said Erika Graffeo, director of marketing for Pandora. "Our focus is providing an excellent product that enables consumers' personalized music discovery.

"We strongly believe in building relationships with our audience and transferring the value of our relationship to marketers and advertisers," she said. "This goes for online as well as other media, such as mobile."

To date, Pandora's marketing efforts have been minimal.

"We are very fortunate that the application is selling itself," Ms. Graffeo said. "Pandora continues to be on the top 10 and is the most downloaded application in the U.S.

"By being in the App Store when it first launched, we got significant momentum," she said.