I understand how basic Optimality Theory (as applied to phonology) works, but I've never understood how it came into popularity. I'm guessing, though, that there are good reasons why it arose.
So what phonological patterns does Optimality Theory explain that rule-based phonology doesn't? (Or, what phonological patterns does OT do a better job of explaining?) In particular, I'm curious about the original motivating examples (if any) that Prince and Smolensky provided when they introduced OT.