One of the important features in SharePoint is the ability to have an overview of the tasks assigned to a person. With SharePoint 2013, the source of the aggregation has diversified including now Project Server Tasks, SharePoint Tasks and Exchange Tasks , all these aggregated in the special "My Tasks" view in each user's personal site.

You will find the information in this document http://www.microsoft.com/en-us/download/details.aspx?id=38799