Wikipedia
AdAway
AdAway is a free and open source ad blocking application for the Android mobile operating system. It was started by Dominik Schürmann of Sufficiently Secure but it is has since been forked. In 2013, it was removed from the Google Play store along with other ad blocking apps. It is currently available on F-Droid.
AdAway blocks ads using hosts files from various locations, and combines them automatically. The user is able to whitelist or blacklist additional webservers, or add a new hosts file altogether. There is an option to log DNS requests to help whitelisting or blacklisting. AdAway requires root access because the hosts file is in the system partition.