Segments

Segments offer you the ability to group contacts based on very specific sets of criteria.

 

Segments are dynamic groupings of contacts. Only contacts that match the Query will be included in the segment.

Your account may have already have some default segments saved in your contacts.  The video tutorial shows you how to make a couple of simple segments and save them to your account.

But, the segmentation tool is very powerful and will allow you to build very complex queries based on a wide range of criteria.