Ads are a [D]DOS on your brain computing power. Targeted or not.
Open street map is a great example, along with wikipedia and numerous open source projects which are either backed by some foundations or collect donations and membership fees. The broader scope here is that while this is a better approach for the world, as long as there is the possibility to earn a buck on some service, there will be a comercial version of it. Guess capitalism just works that way.