Years ago, when I signed up for my Gmail account, I was aware that Google "reads" my email and directs ads my way. I don't care.
For Google's services I pay exactly $0.00. What I get from Google: A free phone number with great phone management SW; free phone calls to/from. free text-messages; free turn-by-turn GPS navigation; free education at Google University (Google Search); free secure document storage, and sharing; free entertainment with YouTube; free language translation (used it in Israel and Jordan last year); free GPS track-file maker; free trip planing tools (Google Earth, Google Search, Google Maps, etc.).
I'm stopping now. I think I've covered the low hanging fruit.
I plotted my navigation on my Nexus-7 from Jerusalem down to Eilat in Israel a couple of months ago. Google saved me a lot of frustration and time on navigating the bizarre "spaghetti"-like intersections and roads out of Jerusalem (a "Middle East" pack for Garmin would have cost me a lot more than I paid Google: $0.00, and Google doesn't charge for updates).
Normally, the only time I click on an ad, is when I see one from Microsoft, Apple, or some other company I don't care for. I know in some cases it can cost the advertiser 50-cents to four dollars or more per click. I know it's trivial, but I feel like I am helping pay for all my benefit.
Without a doubt as far as I am concerned, I am getting the better end of the deal, than Google is getting from me "targeting" ads specific to my emails. BTW, Google, thanks for showing me the ad for Linode.com! I have been a happy customer for about a year now.