I follow people when I see they consistently give good answers that I enjoy reading, either because they are informative or because they are entertaining. Then when I click on the "Connections" button to the left of the screen I can see any questions they may have asked or answered recently.
From my perspective Watson, this feature can be used two ways. Either as described above (option 1), or you can follow people who you think are purposely putting out negative information and offer a better answer (option 2). Hope this helps . :)