http://blog.prepscholar.com/what-is-class-rank-why-is-it-important

Scholarships Some scholarships require applicants to have achieved a certain class rank or percentile (such as top 25% of your class) in order to be applicable. Like colleges, scholarship committees may also use class rank as one criteria to judge a student’s academic abilities, along with GPA and standardized test scores. High School Honors Some high schools award honors to graduating seniors who achieved a certain class rank, such as top 10% or 25% of their class. There are also honors for those at the very top of their class rankings. The graduating senior who is ranked #1 in the class is honored as the valedictorian and often gives a speech at graduation. The person ranked #2 is the salutatorian of the class.