I agree totally with this:
To me its really simple. You can’t monetize web services very well until you have an audience of scale. Jason Calacanis suggests that 10mm monthly uniques is where you have scale. I think it can be less in some cases (highly targeted services) and more in some cases (social nets). But every ounce of time, energy, money, and brainpower you spend on thinking about how to monetize will take you away from the goal of getting to scale. Because if you don’t get to scale, you don’t have a business anyway.
From Fred Wilson’s blog today.