Tim O'Reilly draws an interesting analogy between financial markets and internet services:

One of the real wake-up calls was the way that Wall Street firms moved from being brokers to being active players "trading for their own account." ... Bill Janeway [points] out that ... "now, the direct investment activities of a firm like Goldman Sachs dwarf their activities on behalf of outside customers."
And sure enough, there is lots of evidence that this process is already far advanced [in web services]. These sites, once devoted to distributing attention to others, are increasingly focused on consuming as much of the user attention as possible. What else do you make of Google's recent sally against Wikipedia, the so-called knol....
As Google's growth slows, as inevitably it will, it will need to consume more and more of the web ecosystem, trading against its former suppliers, rather than distributing attention to them.
Update: Y'know, on reflection this is one of those analogies that make less sense the more you think about them. Like, Wikipedia isn't Google's customer. It's not Google's competitor, either. As O'Reilly himself says, it's a supplier. A better analogy would be when a car company decides to stop getting a certain part from a subcontractor and starts making it in-house. Which, when you look at it that way, big whoop for everyone but the subcontractor.