Contact segments can be used in many ways. It all really depends on what kind of information about your recipients' behaviours you want to have handy. Below you can find few examples of segmentation purposes:
I want to know which contacts most often open my emails
To create this segment, go to Filters menu, choose Opens criterion and define their number. Then save the results as a segment. It will refresh itself on a regular basis to show the latest figures from the history of distribution.
I want to know which contacts write about my brand most often:
To create such a segment, you will need the Coverage criterion. As in the above case, you can specify the exact number of publications. Nonetheless, this filter obligates you to add links to such content generated by your contacts to their cards, as Prowly does not automatically monitor references and mentions about your brand.
I plan to reward those who read my press releases most often:
When filtering contacts, use Opens and Click Rate criterions, as the second one will tell you how many journalists actually clicked the link to your press release after opening mailing.
The above examples illustrate only basic segmentation possibilities in accordance to your contacts' behaviours and reactions. Certainly, over time you will develop your own method of organizing database when it comes to the criteria you can choose from.
Also, check how to create segments by tags.