When startups respond to the question of "How will you make money" with "We'll get VC funding", you know there is a problem.
Here's a bigger problem: It seems that the set of people building the next big thing social whatever and looking for VC funding and the set of people who know about business stuff and lead generation rarely intersect.
This is the great paradox of the valley: It seems that most of the people who know about sales, driving traffic, etc and are thus most likely to succeed are building unsexy businesses in web hosting, B2B services, etc. In other words, the kinds of businesses Valley investors are not interested in it all.
The people who are clueless about marketing or generating revenue get the lion's share of the funding...because they're making a social iPad app(or whatever is hot at the moment).