Wise words from Ian over out Crack Unit.
"Whenever you have an idea, or someone else has an idea that requires participation, just ask them (or yourself) one very very simple question: 'Would you do it?'. You may not be the target audience, but you’ll know, deep down, if what you’re suggesting is right"
It's all to east to fall into the 'let's do the user-generated-content-thing' trap. I know because I have done it. On many occasions. It's the current glib suggestion de jour.
Sometimes it IS the right thing to do. Other times it isn't - just because it's flavour of the month, doesn't mean it's right for everyone (next it will be 'let's do that Wiki thing'!).
And don't forget the 1% rule: that only 1% of visitors to your site will generate content, and only around 10% will properly interact with it.
That isn't necessarily a bad thing. Bu know what you getting in to, and make it as easy as possible for the maximum number of people to contribute.