So, I find the text substitution feature annoying, and I've turned it off ALMOST completely. The only app I use that I know actually uses Snow Leopard's substitutions is Adium X. I don't have any other apps that I know to use these, so I can't test whether it's Adium or OS X doing this, but... When I type two hyphens, they get turned into an emdash. This might be a great feature in some strange parallel universe where an emdash was the decrement operator in C. It's not a great feature in this universe. However, I can't find this substitution in the language/text preference pane, nor can I find it in Adium's settings... I'm stumped. ETA: I created a substitution rule "--" to "--", and that's made it stop, but it does not sit well with me for OS X to have no way at all to disable this feature.