Many confuse the terms Feature, User Story and Task. I believe it’s important to grasp the difference between them as each one serves different purpose and sometimes even different audience.
Feature
Feature is a detailed experience of how your users will do something with your application. In order to make “something” meaningful, a Feature must include (1) the reasoning behind it, the motivation, “the goal”, “the pain to solve” – without it, it’s simply impossible to judge Feature’s ROI in terms of value versus effort and money. Once this is in place, Feature should include (2) user flows. A user flow might be “User can click on the delete button to delete his record, this will popup [a message] for him to verify first”. Usually, a Feature will be built from multiple flows, edge-cases and wording to make sure the grand experience is fully complete. To help relating flow with look & feel, a Feature should (3) include mockups and other accessories. Lastly, (4) business (and even technical) notes should be added to wrap up the experience: URL structure, SEO considerations, user messages user, analytics requirements etc.
Language: customer’s lingo.
Estimation Size: Ideal Days / Story Points / T-Shirt sizes
Clients: Internal and external: development/marketing/business/analytics teams and also your customers (to share with them on feedback forums, blogs).
To Include: (1) reasoning (2) flows (3) mockups and (4) business/technical notes.
User Story
User Story is a single “user flow” from a Feature I described above. “User can enter his password and re-enter it for password verification. If the passwords are not matched, the system will show a message”. Another example: “User can enter his password; the system will check the password’s strength by [rules] and notify the user if the password is not strong enough”. By itself, from User Story is hard to understand the entire picture, but it’s a smaller unit of work to plan and execute by.
Language: customer’s lingo.
Estimation Size: Ideal Days / Story Points
Clients: mostly internal, sometimes external – some User Stories just don’t make sense on their own, without the Feature as complete background.
To Include: (1) flow (2) mockup and (3) business/technical notes.
Task
A task is a specific “todo” with a given work estimation. A Feature can be broken into multiple tasks and so does a User Story. A task will be something like “Add new column to database called Rate and model it in the application – 1 hour of effort”, or “create javascript function to validate input on price field – 1.5 hours of effort” or “create landing page for our campaign with Nike and connect it to our analytics system – 3 hours”. Task resolution will always be much smaller and much more technical than Feature or User Story. It will explain what to do rather than why.
Language: development/marketing/business lingo.
Estimation Size: Hours
Clients: internal only!
To Include: technical information needed.