1. The latest to add on to the growing web of spams is repackaged android applications.....though till now most of the descried repackaged applications are not reported to have any malicious code in them and also like the genuine ones they are also made available for free. These effected applications have the same module as the original, but include an advertisement module ,thus developers of these apps try making money off the clicks on the advertisements.
2. The thing is easy on part of the developers since it is easier on thier part to just fiddle with original Android apps which are written in Java and are, therefore, easily cloned.....
3. Thanks www.f-secure.com