Opus Capital partner Ken Elefant says that you need a billion page views or more a month to make it as a web 2.0 company. This would already put you into the likes of Google, Yahoo, MSN, and others already, unlikely to need any funding, VC Money or otherwise, although it might be good to have them on your board of directors. Cnet States:

Here’s how Elefant comes up with his math. A web 2.0 company needs to be pulling in around $5 million in revenue a month to become an independent, viable publishing house. The average CPM is around $10. About half of the inventory on a given site remains unsold so the real CPM is closer to $5. Thus, you need 1,000 CPMs a month. A thousand impressions go into CPM. Source: CNet

Either way you slice and dice it, the money won’t come in when you don’t have enough page views or make enough money off of ads, but once you get there, everyone will want to invest in you, meaning its better to sell out before the magic wears off.