This document summarizes a 1-year empirical study of user-generated content funded by the National Science Foundation. The study included online surveys of 411 video game players and 46 industry professionals, as well as content analysis of 3,300 pieces of UGC across various platforms. Key findings include: 1) The majority of gamers create and enjoy UGC but only half share it online, 2) Motivations for UGC differ based on demographics, 3) Most UGC is original rather than referencing existing works, and 4) More flexible creative tools correlate with higher copyright issues in UGC while constrained tools produce less referential works.