"System-wide" text replacement in OS X

I type ° a lot, so I set up OS X to convert *o to that. It's quite easy to do in Word, but not as obvious in Safari.

First, go to language and text to set up conversions. There are some default ones already there. I also type (C) a lot, but I don't want ©, so I disabled it.

Next, you must set up replacements for each application. Type some text into a text box in Safari, select it and go to the Substitutions menu.

Enable text replacement.