Facebook has an embedded algorithm that keeps track of just how you communicate with your friends and afterwards kinds as necessary. Resource
Facebook Search Friends List order
While the precise ranking formula is secret, it does consider the following factors:
* Just how usually you see your friends' accounts
* Exactly how usually you click on your friends' links
* Photos/tags in common
* Usual groups/ associations
* utual Friends
* Exactly how often you search for friends
* Loved one appeal (how popular your friends are among your shared connections).
So, the actual sorting is not random, yet rather very carefully crafted to promote interaction as well as site involvements.