Short answer ( http://www.joelonsoftware.com/articles/ThePerilsofJavaSchools.html http://www.joelonsoftware.com/articles/ThePerilsofJavaSchool...) that gave me

Short answer ( http://www.joelonsoftware.com/articles/ThePerilsofJavaSchools.html http://www.joelonsoftware.com/articles/ThePerilsofJavaSchool...) that gave me an aha moment after my first FP class: Without understanding functional programming, you can't invent MapReduce, the algorithm that makes Google so massively scalable. The terms Map and Reduce come from Lisp and functional programming. MapReduce is, in retrospect, obvious to anyone who remembers from their 6.001-equivalent programming class that purely functional programs have no side effects and are thus trivially parallelizable. Longer answer: http://www.joelonsoftware.com/items/2006/08/01.html http://www.joelonsoftware.com/items/2006/08/01.html