The Computational and Storage Potential of Volunteer Computing
  "Volunteer computing" uses Internet-connected computers, volunteered by their owners, as a source of computing power and storage. This paper studies the potential capacity of volunteer computing. We analyzed measurements of over 330,000 hosts participating in a volunteer computing project. These measurements include processing power, memory, disk space, network throughput, host availability, user-specified limits on resource usage, and host churn. We show that volunteer computing can support applications that are significantly more data-intensive, or have larger memory and storage requirements, than those in current projects. 
David P. Anderson, Gilles Fedak