Appropriate Audiences

I went to see the Leonardo DiCaprio movie Inception yesterday with my lovely wife and my son. Before it started as you all know we watch the trailers of the coming attractions. Each one has a tag stating that the preview is approved for appropriate audiences. I have to admit I am a bit confused by that. How do I know if I am an appropriate audience? Is there some website where you get the jist of what an appropriate audience is? Ha ha ha. . . The movie was pretty good. I give it a thumb up. Not 2.