• System unusable - eg an installer results in a non-installed system in the specified environment
• System severely impaired - eg a wiki installer results in a system that works, but doesn't allow edits
• Feature with severe problem - eg a wiki installer results in a system that works and is designed to integrate with apache for access control, but the resulting install doesn't result in the user being challenged for a username/password
• Feature with non-severe problem - eg a feature works as designed largely, but confuses users
• Feature with minor/cosmetic issue - Typoes, skin details

This is just one list, there can be many different ones.

This is often confused with bug priority .

-- MS - 03 Feb 2004