  Theorists and advocates of "remixing" have suggested that appropriation can
act as a pathway for learning. We test this theory quantitatively using data
from more than 2.4 million multimedia programming projects shared by more than
1 million users in the Scratch online community. First, we show that users who
remix more often have larger repertoires of programming commands even after
controlling for the numbers of projects and amount of code shared. Second, we
show that exposure to computational thinking concepts through remixing is
associated with increased likelihood of using those concepts. Our results
support theories that young people learn through remixing, and have important
implications for designers of social computing systems.
