Guest lecture given for the Metaliteracy MOOC, which is facilitated by Trudi Jacobsen and Tom Mackey. Unit description can be found at http://metaliteracy.cdlprojects.com/week2.htm. Session recording available at https://sas.elluminate.com/p.jnlp?psid=2013-09-18.0829.M.0FAB3903494045EFC45539A96FEDFA.vcr&sid=2012301 (Collaborate recording).