Blog or Discussion Forum?

Sometimes it's necessary to choose between two really great ideas. Heath Bar Crunch or Cherry Garcia? Sneakers or flip flops? Oceans or mountains? Hip Hop or classical? Blog or discussion forum?

Like most things it's all a matter of preference. But here are some considerations:

• Conversation Style: Do you prefer being the main voice? Do you have lots of advice or opinions to share? Do you like posting or being online at odd hours? If so then a blog may be more your style. If you prefer more of the give-and-take of a widely open conversation then a discussion forum may be a better fit.
• Collaboration Level: Like the 'style' question above, if you're seeking more collaboration then a discussion forum may be a better fit. Many discussion forums have polling features, calendars and other collaboration tools. Blogs, while conversational, tend to have a main point of view and responses - a more one-way perspective.
• Time: how much time have you got to devote to care and feeding? Both blogs and discussion forums can survive with sporadic attention, both thrive with care and feeding. But if you truly don't have time to moderate (guide, respond to, weed through) your discussion forum you're probably better off blogging as you're able.
• Critical Mass:  do you have a group of like-minded individuals? Or are  you trying to build one? Blogs can start with a voice of one and build as more people comment. A discussion forum needs, well, discussion participants. Do you have them or can you find them?

These are just a few off-the-cuff considerations thrown out on a Saturday afternoon. What would you add?