Extrinsic rewards can be effective and necessary for some students, in particular the students who are below grade level and have not yet experienced much success or social support for reading. Under program conditions, the students learn to become engaged in reading and eventually read for internalized reasons.
100 Book Challenge provides various incentives and prizes to schools for use in recognizing student achievement in reading. Just as students enjoy earning levels of distinction in sports, music, scouting, etc, a similar model can be applied to success in school.
The Principal publicly rewards each milestone that is a multiple of 100. Broader recognition from the surrounding community is also encouraged. See Tips from Teachers for unique methods for recognizing student achievement.