So that any further blocked users get to know that as said in their message! Type YouAreBlocked in between {{}} on the user you are going to block and don't forget to type |(then the reason)|(then the expiry date)! Here is what it looks like:

Smashing Hello, Jackninja5DipperGravityFalls/New Template. You have been blocked for no reason given with an expiry time of none given!