I've been tempted to one up this approach by running a local DNS server that will direct all those ad hosts to a local server, then write a simple web app that will handle all those requests by serving up motivational quotes instead of ads.
The upside here is it becomes an effective adblock for iOS when on the local network. I'm not sure how to extend this so that it will work when my iPhone is on an LTE network.
I think you could set up a proxy server and use Apple's iPhone Configuration Utility to load a proxy for cellular data use. If you're jailbroken, you could also put a host file directly on the device, but it does slow it down a bit.
The upside here is it becomes an effective adblock for iOS when on the local network. I'm not sure how to extend this so that it will work when my iPhone is on an LTE network.