Product management vs. project management

If you want to be a bad product manager, confuse product
management with project management. The words are so close because the two concepts are so similar. Product managers should manage projects since they need to ensure that the projects get done. They’re both management roles (right?) so the skills and experience are virtually the same.
Project managers just get in the way and try to take control of the project away from the product manager.
If you want to be a good product manager, learn the difference
between product management and project management. Despite the similar names, there are big differences between product management and project management. Confusing them is common, even among those experienced in product development.
Project managers are responsible for the successful delivery of a project — a one-time endeavor with a goal, scope, deadline, budget, and other constraints. A project manager will work to align resources, manage issues and risks, and basically coordinate all of the various elements necessary to complete the project. As they relate to products, projects can be undertaken to build a product, to add new features to a product, or create new versions or extensions of a product. When the project is complete, the project manager will usually move move to a new project, which may be related to a different product.
Product managers are responsible for the overall and ongoing success of a product. Once the project to build the product is complete and the project manager has moved on, the product manager remains to manage the product through the entire lifecycle. Other projects related to the product may be initiated, with the product manager being the one constant stream throughout, defining the project goals and guiding the team to accomplish the business objectives that have been defined.
One challenge of the two roles is that they can appear to be at odds with each other. A product manager may want to add a lot of features to meet observed customer needs, but the project manager may want to keep scope as small as possible so that the project is delivered on time and under budget. Traditional definitions (and probably those above, too) often mischaracterize the project manager as singularly focused on getting the project finished on time and under budget without any concern as to whether it meets the market or customer needs.
Good product managers and good project managers are able to create a balance of these conflicts. Good project managers know that the true success of a project is not whether it is on time and within budget, but whether it meets the defined goals and objectives. Good product managers know that all
the features in the world will not matter if the project is continually delayed and never makes it to market or if it is too over budget to be completed.
Especially for web-based and technology products, the confusion between project and product management is common and potentially harmful to organizations who do not acknowledge the distinction. As Rob Grady writes in Are you a Web Project Manager or Web Product Manager? (Part I):
Today, as websites have become increasingly important in business, they are, unfortunately, still being managed as projects. This becomes a problem in meeting defined business objectives, prioritizing, having the right skills to manage what has now become a core business function.