Should the product manager and product owner be the same person?

I recently read the question on the difference between the product manager and product owner on Quora and ended up sharing my opinion – at length. So I’ve decided to publish it here for posterity. Needless to say, there are other answers and other opinions, all equally valid.

The product manager is charged with communicating the voice of the customer — and at the end of the day achieving customer and market success. Meanwhile, agile development teams demand that the customer representative (ak...