Brands such as Sears, Bombfell and Domino?s are leveraging the Android lock screen to deliver full-screen ads via the Locket mobile application.

Locket recently launched in beta test mode on Google Play and saw 35,000 downloads in its first four days. Users see ads when they first wake up their phone and have the option to engage or ignore the ad.

?For brands, they have been having trouble figuring out how do we effectively engage with users on mobile phones because it is very small real estate and people don?t like banner ads or pop-up ads,? said Yunha Kim, cofounder/CEO of Locket, New York.

?This is the best way for brands to be able to communicate with users - it is full screen and users are already opted in so they are more responsive to ads,? she said.

Frequent use
Brand advertisers looking to reach mobile users face several challenges, including that the screen size on smartphones is small. As a result, transferring a desktop banner ad to mobile screen can be ineffective because the ad is hard to see.

Pop-up ads can be more effective but disrupt the user experience and, therefore, are unwelcome by many users.

The lock screen is a good alternative because users check their phones frequently throughout their day, per Ms. Kim.

?Mobile advertising needs another solution,? Ms. Kim said. ?People look at their phones 150 times per day throughout the day, on average, according to Nokia and T-Mobile studies.

?If you multiply that by the number of only Android users, which is 71 million in the U.S., that?s 10.7 billion glances on your lock screen, and yet nobody is using that lock screen,? she said.

Swipable ads
Users can download the Locket app from Google Play. Once they sign up, the default lock screen is replaced with Locket?s lock screen.

When users wake up their phone, they see an ad and can either swipe to the left to engage with the ad or swipe to the right to ignore the ad and go to the home screen.

Users get paid one cent per swipe regardless of whether they engage or not. Currently, Locket is capping paid swipes to three times per hour but it plans to increase the cap once there are more advertisers.

When users reach a minimum threshold of $10, they are able to cash out through PayPal.

Right now, Sears has an ad in Locket that takes users to its Web site when they swipe to the left. However, the plan is to introduce an ad with a coupon in the next few weeks that can be downloaded when users swipe to the left.

The coupon can then be redeemed in stores.

Right moment
The NuFace ads include a coupon code that can be redeemed online for a 20 percent discount on purchases.

Locket is also working with a Domino?s franchisee in California, enabling users to call the nearest store when they swipe its ad to the left.

Other advertisers include Bombfell and Zipcar.

The average click-through rate on ads so far is 8.5 percent.

?There is no other medium that will allow you to communicate with users throughout each moment of their day,? Ms. Kim said. ?When you first wake up, the first thing you do is check your phone, and when you go to bed, you check your phone.

?Our idea was, why don?t we hit those moments and allow brands to communicate with the users on each of those moments,? she said.

Final Take
Chantal Tode is associate editor on Mobile Marketer, New York