I want in this post just to give 2 basic graphic examples of how to use the standard content rollup web parts available in SharePoint. I think this is content aggregation made easy :).
Table of Contents Web Part
Content Query Web Parts
I don’t want to transform this post into another Content Query Web Part technical post, a great example can be found on the Microsoft Technet – How to: Customize the SharePoint Content By Query Web Part by Using Custom Properties (ECM).
Regarding Content Query Web Part, my open question is: how deep is this rabbit hole? I personally find it the most powerful out of the box web part existing in SharePoint 2010.