Is it possible to know if an app has advertisements by analyzing permissions? Or if not, how to see if an app has advertisements or not?
You cannot see that just by checking an app's permissions: those permissions ad modules require for their job are the same the app itself might need for another job. You can, however, look up the app at AppBrain: for each app, that site lists up what ad modules (and other libraries) are used. You find that scrolling down to the "Libraries" section. AppBrain distinguishes between "Development tools" (which also include analytic libraries like Google Analytics or Flurry), "Social libraries" (Facebook &amp; Co), and "Ad network libraries" (Admob &amp; Co).


Libraries used by an app as shown by AppBrain

Clicking on an entry also reveals details on that module/network.