I read a recent article by Umair Haque challenging Silicon Valley to create bold solutions to the world's problems.
I agree with the tone of the piece and with the basic premise that many of the Web 2.0 "companies" are fixing small problems and not as ambitious as they could be. It seems that new Internet companies can be created with so little capital, that the industry attracts many newcomers who think their sheep-throwing "application" is the next big thing. It isn't.
For their part, many venture capitalists have become afraid of the earliest stages, preferring to invest later in a company's development in order to mitigate their risk. This has left the early stage wide open for angel investors and a few brave VCs to step in.
I'm not certain that VCs are interested in changing the world when their fiduciary duty to their limited partners to create the best financial returns is paramount. So I don't see a way out of the current situation of the lack of ambitious imagination, other than the usual shake-out, where companies and their founders are forced out of business by that age-old combination of time and money running out...