Most apps use 3rd-party libraries and servers to show those ads, so they can be blocked at the network connection level (e.g. the hosts file) if you have contro

Most apps use 3rd-party libraries and servers to show those ads, so they can be blocked at the network connection level (e.g. the hosts file) if you have control over your phone's OS. Having Android helps with that. The apps need to handle it gracefully because they can't tell whether the ad server is legitimately down or just blocked. I've never had an app work any worse with blocked ads.