If 'Do Not Track' happens, what's Plan B for targeting?

Despite plenty of conversation and posturing, we're a long way from regulations or even standards for a “Do Not Track” registry as pushed by the Federal Trade Commission.

If “Do Not Track” were to come about, would that be the end of many of the ad targeting forms we have seen evolve on the web, in email marketing and elsewhere on the Internet?

I doubt it.

Geographic targeting gets better with each new consumer conversion from proxied dial-up accounts to broadband. If you visit a site using home DSL, cable or fiber access, or use the mobile web via a 3G or 4G connection, chances are the broadband Internet provider sends along a host name that at least reveals what town you're in, if not what part of town. This targetable — though not personally identifiable — bit of information goes to the site even if you use a browser that successfully anonymizes you and your computer.

What about interest targeting? Before a site knows to serve you ads based on expressed interests, you have to express those interests to the site. On purpose. That by its nature circumvents “Do Not Track,” much the way businesses can still solicit their current and even former customers by phone even if they are on “Do Not Call” lists.

Behavior targeting — serving you a message based on your recent online behaviors, such as sites visited and search keywords — might seem most vulnerable to a “Do Not Track” system. I think, however, it would find serious trouble only in the unlikely event DNT were to gain near 100 percent adoption.

Otherwise, what would stop developers of ad serving software or ad networks from employing statistical sampling methods? Using sampling on a large enough volume of inventory, shouldn't an ad net be able to extrapolate big-enough behavior segments from the observed behavior of even a small percentage of people who do not opt out using DNT?

I leave it to others to debate the ethical, business or technical implications. I'm only saying “Do Not Track,” for whatever comforts it may provide people who sign up, doesn't seem likely to end any of these major forms of online ad targeting. What am I missing?