However this simplification rarely addresses the needs of the total business. Here's a great article on the expansion of this simplification.
The Product Manager vs Product Owner by John PeltierI've worked with numerous teams in my 10 years of guiding Agile transitions. And reflecting upon all those teams, there success levels, the customer & team satisfaction with the product & process, and then generalizing a common pattern - the one key success factor is an engaged person playing the Scrum role of Product Owner. The anti-pattern also holds true. When there is a lack of Scrum's Product Ownership, the teams suffer, the product suffers, the adoption of the process suffers and therefore the original intent of the Agile transition sponsor reason for changing to an agile process such as Scrum will suffer.
At Navteq I saw an engaged product manager take on the role of Scrum PO in the very first session of a 3 day workshop to launch the new team & project. The activity was for the group to write their elevator statement. This person engaged with the activity, intuitively understood that this very abstract vision of the product would set a tone for how the team would understand the value they could deliver to the organization. He did not dictate the statement, but facilitated receiving and sharing the visions he had and integrating the words and phrases that the newly forming team created. After that activity, the group was well upon it's way toward becoming a team. The next day, the PO had committed to memory the elevator statement and could recite it, as well as elaborate upon any of it's aspects. He created a highly aligned team to the purpose they were to deliver for the organization.
Do you need a Product Manager AND a Product Owner?