No. Privacy modes are not the solution to this. Privacy modes cripple the browser in all sorts of ways that are undesirable for everyday use. I do use privacy modes when appropriate, but this isn’t one. Shopping in privacy mode would be a nightmare, since links would not “turn purple” and I’d be looking at the same reviews or sales sites over and over. And even if there were a magical browser mode that I could turn on in this scenario that would do what I want, it would be simply to eliminate the targeted ads from appearing in the future! This is exactly the point!
ETA: And if it were perfect, it would turn on magicallly just when I wanted it to without my having to think about all future annoying possibilities and embarrassing scenarios for every single page I visit. It would be like targeted ads could never cause anything annoying again… Actually, hey, the technology does exist for this: no targeted ads to start with! (Is the point becoming clearer? I don’t care about ads! Why should I be forced to cripple my browsing to prevent problems from them? Why shouldn’t I be annoyed at advertisers for them?)
Here’s my concern with it: I don’t know what pieces are being stored and correlated.
Here’s an example: I have no problem if GMail reads my mail, sees that I’m talking about taxes and bankruptcy with my client who offers auto repair, and uses key words in the e-mail to try to show me tax, bookkeeping, bankruptcy and auto repair ads. This is fine, assuming the data is being mindlessly used to generate ads and then tossed. In fact, I might even call this a feature.
I do have a problem if GMail permanently stores these keywords in a database and then, when my client uses his e-mail address in another site, Google’s database says “Aha! Remember that e-mail when this guy asked Dracoi questions about taxes and bankruptcy?” I’m doubly concerned because it’s my clients’ information. It’s one thing for me to assess the risk that I’m willing to accept, and another for me to expose other people to that risk when they have no say over it.
Now, I’m not saying these connections are currently being made the way I describe, but they could be. I’m not even saying it’s Google that I distrust. There are so many ad networks that I know nothing about. I’m not going to get angry or paranoid, but I do feel like caution is necessary.
Why send a steady stream about your activities to anyone? There’s little to nothing in it for you. You may depend on security through obscurity but that is not 100% reliable by any means. Also, you may reveal only a little on a day to day basis, but over time databases can tie together a surprising amount of information. It’s like I say, easy and rapid compilation and dissemination of information works both for and against us.
Personally I use FlashBlock, Adblock, and Ghostery. I also surf inside a Sandboxie “sandbox”. Having taken precautions, I then surf like anyone else. Practice safe surfing.