I was going to cite the TOS, but it looks like it has been updated into a more general TOS since the launch of Google Voice. There is now a clause that says the scanning of emails is automated and no human will ever read your email, which is common. I can promise you this has not always been the case. The point I was trying to make still stands, you use the free email service and this gives value to google.
Really though Ben, your post is agreeing with what I have said and only attempts to engage in name calling based on your misconception of the point being conveyed.
If you login to your gmail account from home and work, they can easily identify the two computers and based on the timing extrapolate your schedule. Let's say you don't use gmail, but you go to the same blog several times a day and login to post comments, tracked. They even track the individual items you buy on an ecommerce site and what you paid for them. They track how many times an item was added to a cart and removed, then at what SRP it was finally actually purchased.
Now I'm not offended because I could easily fall into the 'tinfoil' hat crowd I suppose, which things to be what happens when you point out all the data google is actually gathering. I'm not saying that Google is evil or that you shouldn't use them, I'm just saying the service isn't free. Just because we personally can be ignorant to the true cost doesn't mean it cost nothing, or that we should feel indebted for that matter.
I use google, but it scares the shit out of me when I look in aggregate at the analytic page of a large e commerce company, my own web history (which proves they can link it back to an individual), the fact that the gmail user agreement says they will read your email, or the fact that street view collected my wifi information and tied all of this back to accurate lat/long coords, or the recent harassment scam that proved google links multiple gmail accounts to an individual for internal tracking purposes, that they can access all of your google voice and chat history, or the implications of all that when combined with GoogleTV or the fact they are in bed with the DoJ.
As I said, I'm ok with these things and continue to use google and have no plans to change, I make no suggestion that you should change your habits. I just think it's naive to think you give nothing away. We intrinsically trust the little white box, when really we shouldn't.
Everything runs on opportunity cost. You may have heard of the old adage "There's no such thing as a free lunch", it's the same theory at play here, "There's no such thing as free search.". Google isn't the most valuable company on the planet because of their search facilities, but because of the wealth of data they gather on end users and consumer habits.
Not arguing that searching isn't great, just saying if you were given the same option to give data on your habits, what you read, where you bank, when you're at work, at home, let them read your emails, etc, to an individual in exchange for them looking things up in a library for you, you would say no without hesitation. We give all this information to google who in turn uses it to make Billions of dollars.