If you don't want to share anything, then don't use the app. Nothing is automatically sharing unless you tell it to. Nothing can magically share the fact that you read a Techcrunch article unless you install a "Techcrunch Reader" app or something, in which case it would have to ask your permission to share that information. If you didn't like it, you can remove that permission. For example, here's the relevant permission from the Washington post app:

Add app activity to your timeline Washington Post Social Reader may publish your app activity to your timeline.

If you don't want the app to automatically publish something, then just x out that permission.