It appears that a Project Manager is mainly responsible for the implementation of the project, controlling its progress and processes, monitoring project’s scope execution and establishing clear communication between team leaders and other stakeholders. Most commonly, there are several Project Managers in a company depending on the complexity of the projects.
A Product Manager, however, is in charge of the entire product, covering all the stages from idea to post-production and post-investment analysis, taking into account business, marketing and programming interests. A Product Manager should always question him/herself: What are we creating? What problems do we solve with our solution? What benefits will it bring? How can we improve our solution?, etc.