In a recent article, I read about increasingly intrusive tracking of online users, which has lead to a proposal at the FTC,

FTC Chairman Jon Leibowitz said the system would be similar to the Do-Not-Call registry that enables consumers to shield their phone numbers from telemarketers.

Maybe I’m dense, but even if this weren’t a fundamentally bad idea for policy reasons, I don’t see how it could work.

The phone system is regulated to the extent that there is a well defined set of phone numbers, and the overwhelming majority of phones used by consumers have one or perhaps two numbers. If I travel with my mobile phone, its number stays the same no matter where I am. A phone number is a fine identifier to use in the no-call database.

For do-not-track. what’s the identifier? Your IP address? Most ISPs assign addresses with PPP or DHCP so they change anywhere from once an hour to a few times a year. My ISP uses a “carrier NAT” so that their residential customers have no unique external IP address at all. When I travel with my laptop, I get whatever IP a hotspot or hotel happens to assign me, typically hidden behind a NAT. And on a lot of ISPs, when users fetch web pages, the remote site sees the IPs of the ISP’s web cache, not the individual users.

As an alternative, for web tracking, I could imagine that the FTC could ask the IETF to invent a no-track header to be sent with each HTTP request, along with all of the other options like preferred language that a browser sends now. But that header has to be programmed into every web browser, every mail program that renders HTML mail, every web server, and every web cache and proxy, which, if we’re really diligent, might cover half of the users in two or three years.

Even if we do have a no-track header, we’re still in the situation other people have outlined, with bad guys just ignoring it, and little way to even tell that they’re doing so, much less get the FTC to act on it.

In my experience, the FTC is not dumb, so my most charitable interpretation of this proposal is that they know it won’t work, but they figure they have to show they tried and failed before they can go back to Congress and ask for something reasonable, like only track people who opt in and say it’s OK.

In the meantime, Firefox users might enjoy a browser add-on called Ghostery which lets you see how many trackers web sites offer you (a lot, it’s impressive) and decide which of them you want to accept.