I won't put a huge post here, as I have already been discussing this issue in several long blog posts;<a href="http://gomiso.blogspot.com/2011/07/g-and-beyond-whats-your-target.html
">the latest is here.</a> You can find several exhaustive posts searching my blog for the phrase "the politics of information."
Moggs Oceanlane's comment is very pertinent - I have spent over 25 years online, investing my name (s) with respect and accountability from my communities. I have recommended thousands of dollars of purchasing power to various companies using those names based on my reputation and skills. You can track and profile my name, and you will have just as much information to target ads to me as you would using my government-sanctioned "real name" (which I am changing legally to my online handle). You certainly would have more information to target ads to me under this name then you would under a legal name, which I have taken great pains to keep <i>off</i> the net, knowing as much as I do about the state of security, that data breeches are most-often inside jobs or negligence and the lax and laissez-faire handling of databases prevalent in the industry.
If someone would like to sacrifice all that goodwill in product recommendation from a knowledgeable and trusted technician, that's their choice. It's not like I need Google or its products; I have grown up with the net and I know there's much more out there than one company (including alternate search engines, trustable email and social connections). I'd point to Sony and nVidia as examples of people who squandered years of word-of-mouth recommendations and sales for one quick quarterly bump only to savage their long-term reputation.