Getting back to consumers, their data is really difficult to take back. It is not as if the data exists in only one place and can easily be deleted. That simply isn't how it works. Once duly authorised and collected, consumer data gets plugged into dozens of databases and shared with just as many departments, consultants and partners. The data is parsed and backed up, and the chances that anyone can accurately list every place where that data exists are roughly nil. That's why it's ludicrous to believe that you can change your mind and demand that all the data you let a company collect be removed. Block it initially? Sure. Get it back later? Not going to happen. There will always be copies floating out there somewhere.
And that's true even with the anonymous/aggregated approach. Yes, a company that aggregates the consumer data it collects only analyzes that data in the aggregate, and the aggregated data is anonymous. But all that data arrived in unaggregated form and far from anonymous, and that raw data certainly still exists in a database somewhere. Probably more than one, which brings you back to the question of how to corral all those data roaches that are running around the company's systems.
The cynical view of all this is that corporate advocates of privacy want to offer consumers the illusion of privacy control without having to deliver actual control, since the consumers have no way of knowing whether the data they have decided to "take back" has been actually removed. It's the business equivalent of the time-honored politician's trick of voting against a bill unpopular with constituents, knowing full well that it will pass anyway.
I can think of no practical way for a Wal-Mart, Exxon, Nabisco or Hilton to remove specific pieces of data once they've been absorbed. That means that corporations are going to have to stop making consumers privacy promises that they can't possibly keep. Assuming, of course, that you want to be honest. If you don't, that's something you really want to keep private.