Over the past four years, mobile application support has grown from a mere handful of games and applications to just short of one million applications, accumulatively. A large portion of said applications are paid, meaning the end user must make a one-time payment and the application is theirs for life. The remaining applications are free – some are entirely free (no ads) and others are ad-supported. With the immense growth of the availability of applications, the advertising, too, has evolved.

We have all seen in-app ads in several shapes and sizes and in all of their screen hogging glory. More recently, however, AirPush and SlingLabs have introduced their own style of push notification advertising, a new method to deliver ads that will supposedly increase click-through rates (CTR) up to 40 percent without interrupting the users' in-app experience. These two mobile ad services offer products that utilize the drop-down notification window of your Android device to deliver such advertisements.

Let me begin by saying that advertisements do not bother me – it's a way of life and the way the Internet supports itself (we wouldn't be here without them). Free apps are no different, and in-app ads are a necessary evil that the developers need to and should use to earn money for their hard work. That said, there is a limit to how often the ads should appear or how “in your face” they should be. As long as in-app ads are not over the top, I have no complaints with them, especially because there is usually a paid version of an ad-supported app that will remove the ads altogether.

But that is the extent in which ads should appear, within the app itself. The moment an advertisement leaves the boundaries of its host application, it becomes intrusive and spam-like. AirPush and SlingLabs employ your notification shade to display the ads of applications that use their service. Not only does this mean that ads will appear amongst your notifications, but if you have an application installed that uses the service, you do not even have to launch the application for ads to be pushed to your device. Ads will intermittently disguise themselves among your new text messages, emails and various other notifications. Ouch.

The mere thought of my notification space being used for advertisements makes my skin crawl. I will immediately uninstall any application that begins to send ads to my notification shade – and no, I will not be purchasing the premium version, I will be looking for an alternative. The notification area is for my ... well, notifications which are typically important and time-sensitive. Ads in this space will ad clutter and inevitably make me click on the wrong thing (hence the improved CTRs).

Unfortunately, these two services are perfectly within their legal boundaries. The ads act as actual push notifications from the application itself, turning your notification window into a billboard for AirPush and SlingLabs to use at their disposal. With claims of improving a CTR up to 40 percent, I fear developers may pounce on the deal. If they do, they will also face some rather daunting consequences.

Quite frankly, I'm irate about this whole idea and feel Google should step in and put an end to this before it has a chance to infect all of Android. Quentyn Kennemer of Phandroid shared his thoughts on AirPush back in April and well, he wasn't too happy about the idea either. At the bottom of his article, he included a poll asking, "What do you think of AirPush?" At the time of writing this, 2,336 voters had taken the poll: 93 percent voted that AirPush has not place on Android and just over 3 percent voted, "I think developers deserve to more effectively target users."

Kennemer also notes that the first application to use AirPush's service, APNDroid, received mountains of negative feedback and was reported as "malicious" in Android Market to the extent that Google removed it temporarily. The application has since been republished but the developer stated that he learned his lesson and will never use AirPush again.

How do you feel, readers? Are these push notification advertisements the future of mobile advertising? Or should Google put an end to the intrusive service? Furthermore, will these services capsize themselves by appearing spammy or malicious?

Image via AndroidAndMe