What might come of employing Web 2.0 openness and collaboration? Does it add value to have more and more content from more and more people? Value to what? To whom? Under what circumstances?

Where’s all this going, do you think? What’s the benefit in Web 2.0 community contribution, in your opinion? Do you see a downside to more participation, self expression, offerings from individuals? 

Any precautions and safeguards you want to recommend?