It's a term from agile development, a programming methodology. Every project has 2 backlogs: a product backlog and a sprint backlog. At the start of a project, a project backlog is made and all kinds of things are added to it without any care for project scope. You just throw ideas at the project to get as much as possible within the context of the project. Then, the sprint backlog is created. A sprint is a predetermined amount of time in which devs will develop certain areas of the project. They take on certain pieces of the product backlog that they think they can get done in the allotted time. Then a spring begins, and no one is allowed to bother the devs with anything except sprint related things. Now say that during a sprint, another person comes in and says "you know what, it'd be cool if we had X." That's fine, it gets added to the product backlog and MIGHT be taken on during the next sprint.

Now that we've got that little introduction out of the way, it's easy to understand that when a project has been completed, there's probably still things left in the product backlog (because some ideas can't be developed within the allotted time). Those ideas of various projects past (or just ideas that have come to the table in general) are sitting there gathering dust until a project manager decides it's time to clean house, take those dusty old ideas out of the bin and give then some love. What Mod Osborne is working on is giving us the tools we need to have a say in those things. We'll be able to say, as a community of stakeholders (a term from agile for anyone who's involved in the product, which can also include the consumer), "hey, we saw that X is in the product backlog, make sure that gets worked on please."

I haven't worked scrum in a while, but that's the rough gist of it. I hope it makes more sense now. :)