It said on its official blog:
http://news.google.com Oct 19, 2015
Apple removing hundreds of App Store apps as advertising SDK found to collect sensitive user data via private APIs – 9to5Mac
Oct 19, 2015
Code analytics platform SourceDNA has found hundreds of apps on the App Store that used private APIs to collect private user data, like email addresses and device identifiers, slipping under Apple’s radar in the approval process. The code got into these apps through the inclusion of a mischievous third-party advertising SDK, which secretly stored this data and sent it off to its own servers..