Adblock Plus for Android (ABP) uses the proxy approach for ad blocking, i.e. a process is continuously running in the background, listens on a specific TCP port (which is 2020 nowadays) for proxy HTTP requests and processes them based on it's ad filtering rules. If you're phone/tablet is rooted, ABP can automatically route all outgoing traffic through it's proxy. If your device is not rooted and it's running a more recent (4.2.2 or newer) Android version, then you've to manually configure your network connection to use ABP's proxy. The essential problem with this approach is that it can only process plain/unencrypted HTTP connections, while today most services go through HTTPS (SSL encryption). Let it be Facebook, Google or even warez sites like The Pirate Bay. ABP for Android is of little to no use on these sites. The only possible solution in this case is an in-app ad blocker. The Android version of Firefox does let you install the ABP extension, which will block even ads served via HTTPS/SSL. So you've a choice, even though somewhat limited (since you cannot use the browser of your choice ... you've to use Firefox if you want to get rid of HTTPS ads).