User blog comment:SniperGhost/Wiki Adoption/@comment-2253300-20110204012843/@comment-2253300-20110204025657

Gw's marketing aside, there are other reasons why they are so popular. First they represent the best that 40k's humanity has to offer. Also, to a 40k noob they represent the good guys. Finally, and admittedly this ties into marketing, no other faction has quite as much established background as they do. It is easy to see why most people get hooked on the Marines first.