AdAway blocks ads on all sorts of Android apps that allow you to surf the web. The ad blocker is open-source and uses host files for ad blocking. If an app sends a request for an ad that request will be redirected to 127.0.0.1, i.e. localhost. Simply said, the request goes nowhere and no ads are served.
Ranked in these QuestionsQuestion Ranking
Pro System wide blocking
Use the hosts files to block ads, so it works for everything.
Pro Doesn't consume CPU time or memory
The app updates the hosts file periodically but doesn't need to run in the background in order to block ads, which is especially convenient for older phones.
Pro Can use systemless host
Can be used without modifying the system if rooted with magisk.
Pro Can use custom host files
Lots of people and keep their own updated host files used for blocking ads and ad away supports loading them in or even adding their source for autoloading.
Con Needs root (by design)
Needs root to update the hosts file.
Con Won't block same domain ads
Because the host file can only redirect domains, if the ad and content are on the same domain the ad will be displayed.