Sure, developers of free apps have to be somehow paid for their work, as web sites have to be somehow paid as well and ads are always an easy way to make some extra money for - very often - high quality apps which are available free of charge from the mobile app markets. However, a less nice side effect was recently documented by researches from the North Carolina State University and Purdue University, Indiana which have found that including ads in apps not only poses privacy and security risks but also figured out that up to 75 % of the energy used by ad-supported free versions of Android apps is spent on serving ads or tracking and uploading user data.
This means that running just one app could drain a smartphone battery in around 90 minutes. The discovery was made after Abhinav Pathak, a computer scientist at Purdue University, and colleagues developed a software to analyze apps' energy usage. When they looked at popular apps such as Angry Birds, Free Chess and NYTimes they found that only 10 - 30 % of the energy was spent for the app's core function.
According to the "NewScientist", in Angry Birds only 20 % of the battery power is used to display and run the game, while 45 % of the energy is wasted to find and upload the user's location with GPS and then downloading location-appropriate ads over a mobile broadband connection. According to the research's findings, the 3G connection stays open for around 10 seconds, even if data transmission is complete, and this - so called - "tail energy" consumes another 28 per cent of the app's energy. Pathak blames the energy leakage on inefficiencies in the third-party code that developers use to generate profit on free apps. He will present the research at the EuroSys conference in Bern, Switzerland, next month.
While North Carolina State University's research wasn't about battery consumption- but privacy concerns-related, the study of 100,000 apps in the official Google Play market noticed that more than half contained so-called ad libraries.
This means that more than 50 % of the apps potentially drain the battery in the background and that this isn't just an Android problem but affects all mobile platforms including Windows Phone and iOS. The bottom line is that developers should either reduce the access of resources, like GPS, etc. to reduce the battery consumption as much as possible or that users should better purchase an add free version of the same app. However, this doesn't mean that ad-free versions are not using access rights for unnecessary tasks because quite often developers leave the core code as it is but just removing the ads from pay-versions.
Cheers ~ Arne