Distributed Computing is a new form of online collaboration; such projects divide a large computational problem into small tasks that are sent out over the Internet to be completed on personal computers. Millions of people all over the world participate voluntarily in such projects, providing computing resources that would otherwise cost millions of dollars. However, Distributed Computing only works if many people participate. The technical challenge is to slice a problem into thousands of tiny pieces that can be solved independently, and then to reassemble the solutions. The social problem is how to find all those widely dispersed computers and persuade their owners to participate. This article examines what makes a collaborative Distributed Computing project successful. We report on data from a quantitative survey and a qualitative study of participants on several online forums, and discuss and analyze Distributed Computing using Arquilla and Ronfeldt's (2001) five-level network organization framework.