Questions:

• Does your content need to change often?
• How many authors are providing you with content?
• Do elements of that content have time value or a predetermined 'life cycle'?
  (lifespan, prioritization, persistance / or archiving)
• Does that content need approval or does it have a predetermined editing process?
• Does your site need a high level of interactivity? (Online forums, etc.)
• Complex forms?
• Personalization?