Google acquired Doubleclick this last month. This is huge ya'll.
Think of Google as the most personal diary all searchers use. We google search our dates, "how to commit suicide", "medications for depression", "new job", "dirty bomb", etc etc. I would argue we get more intimate and revealing with Google than we would in our own journal or diary. You think Google doesn't take advantage of this? Google knows what people want, when they want it, and where they are looking for it. Google gets about 80% of search volume (or something ridiculous like that). They have a more accurate assessment of the American culture than ANYONE.
Now they have the targeting capabilities of a Double Click? OMG. This is great for the economy because ads are going to a whole nother level of precise, timely and targeted. We're talking about sandwich ads showing up to someone who visits www.subway.com often. Different ads showing up if the stock market just went up or down specific to company and stock. Basically it's Google mapping their knowledge of American culture to DoubleClicks's targeting abilities to serve up a the exact product offering you want at the time you want it. Good for economy but a bit scary for the end user.