A product backlog is an ordered features list, containing short descriptions of all functionality desired in the product.

Some characteristics are:

• Typically lists features, functions, requirements, enhancements, and fixes that are desired in the product. Technical work and knowledge acquisition also belong in the product backlog
• Product Backlog items can be of varying size, effort or complexity
• Backlog items selected for the upcoming Sprint are fine-grained and so that any one item can be done within the Sprint time-box
• Multiple Scrum teams often work on the same Product Backlog; an attribute is used to group items

The Product Owner is responsible for Product Backlog, including its content, availability and ordering.

Typically, a Scrum team and its product owner begin by writing down everything they can think of easily. This is almost always more than enough for a first sprint.

The Product Backlog evolves (allowed to grow and change) as more is learned about the product and its customers.