Allowing users to receive without giving content:
1. Good: Maximizes the impact of your PR/ Lets you grow really fast over a short period of time.
2. Bad: Easy come, easy go. Since the users have no role as a content creator, they will be out of there the second your competitor has the slightest feature improvements over you.
Requiring every user to be a creator (edit- to receive full benefit from your app):
1. Bad: The start can be rough. Expect to have to really have to use some marketing ingenuity.
2. Good: Users will be locked in.
3. Good: Your site will (should) be far more valuable if more people are contributing. This, along with #1 will lead to exponential growth.
4. Maybe bad: With this abundance of content, it will be mandatory that you find a way to present the user with the content that is most relevant to him.
5. Good: You are monopolizing access to a lot of content. You can probably charge users directly for this access.
Thoughts?