A product backlog is a list of high-level product requirements (or user stories), prioritized by business value (typically determined by a product manager or product owner). It contains entries for any and all work that is performed, including bug fixes. As new requirements are gathered or submitted, they are inserted into the backlog at the position that best represents their business value with respect to requirements that have already been entered. As requirements are met, they are removed from the product backlog.
A backlog gives a clear context to discussions of priority. Anybody can go and look at the backlog to see the position of something they have a stake in. If it is lower than they think it should be, they can examine the backlog to see what is higher in order to help frame a discussion around either moving it higher or moving other things lower.
So, if you were starting a software company with your own hard-earned cash, would you use a product backlog or wouldn't you?
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