Paul Buchheit: Google buys DoubleClick, for a double-dose of advertising
paulbuchheit.blogspot.com
paulbuchheit.blogspot.com
Google can't lock out or force it's products onto its users, they're in a very different business and environment. In order to continue grow they'll have to innovate - users can easily switch to other services by a click of the button.
As for Facebook being the new Google, Google reinvented a business, internet advertising. Facebook has a great product, but they haven't shown that they can monetize the way Google did to search.