"If someone could next show what makes type systems so interesting in terms that I'll understand then I'll be well on my way into the modern functional programm

"If someone could next show what makes type systems so interesting in terms that I'll understand then I'll be well on my way into the modern functional programming world.. :-)" That question is very weird. Not all functional programming languages are statically typed (btw the answerer specifically mentions that we're talking about static typing here). For example I'm having lots of fun with monads in Clojure right now. Very functional. Not statically typed at all.