So most people are familiar with “projects”. Something you do, have an end goal, usually a budget, resources, plan, etc. Sometimes you have projects within projects. Like a good example may be thinking of the next version of Microsoft Windows as the main project and revamping solitaire for the next version as the “epic”. Your end goal is to keep your main project moving forward, and do stories that apply to that project, but you also might run into mini projects along the way that could cross over numerous sprints, and you want to “group” like/similar stories together to form an “epic”.
What is nice about epics is they still let you do your sprints, and stories as normal,but you have a more higher reaching goal to get a set of stories complete to complete your epic. It also lets you look back and then see how many stories and points you did toward that epic and understand the effort,etc that went to completing it.
Use epics to group stories together to form a common goal for a similar “thing”. It will let you say “let’s focus on the blah epic” and you can make sure you get that piece of functionality done and track it and see all those stories together in the end.
P.S. Blogged from my iPad