Greenspun is also wrong about what singularity is. Afaik its the point where human as intelligent agents build a better intelligent agent than ourselves. That new agent will do the same ,leading to agents of increasing intelligence. There isnt a date fixed on that event (as he says) and the debate is still whether this is posible or not. You have an interesting essay on that at http://www-rohan.sdsu.edu/faculty/vinge/misc/WER2.html