Why IP Tracking Is A Bad Idea

Here is a recent article I wrote for AdExchanger
discussing some of the
privacy issues surrounding the tracking IP addresses, why it should be
regulated, and why using browser cookies is a better alternative. Below
is the full article :

IP addresses are the fabric of the Internet— they are the “To” and
“From” stamps that make delivering messages between computers possible.
While they are necessary to route information from computer to
computer, they can — in many cases — be traced to a human or, at least, a
household. That means they can be used to track people’s online
behavior in a way that eliminates their anonymity online, which bodes
poorly for the future of the internet.

Users should be anonymous when they aren’t logged in

While new technologies that enable content personalization can
provide substantial value, users must also be assured that their
identity is protected for legal, ethical, and safety reasons. Consumers
should have the presumption of anonymity when they are surfing the
Internet and not logged into a site, and they should not be tracked –
either by the government or private sector – in a way that eliminates

To ensure consumer safety and the Internet’s continuing growth, the
presumption of anonymity is paramount. In particular, third-party
services like ad networks, widgets, and off-site platforms like Facebook
Connect, should maintain individual anonymity. They should not be able
to see someone’s cookie, IP address, or browser information and know
exactly who the person is.

IP addresses are
personally identifiable

IP addresses should be thought of as privileged information. From
our tests, IP addresses perfectly identify about 30% of U.S. households.
That means that from IP address, a site can know your exact address.
My home IP address, for instance, has been the same for over four years.
If consumers understand that their exact browsing habits can be tied
to them individually, their wariness will slow their use of the

The EU took an active stance on IP addresses in 2008, declaring IP
addresses as personally identifiable information (PII). This is an
important first step because IP addresses are PII. That said, even the
EU would admit that IP addresses do not always directly correlate to a
given person. Laptop users frequently change IP addresses as they move
from an Internet café to work, for example, and ISPs often dynamically
swap out IP addresses. An IP address can sometimes only give
approximate location, and may be shared across many members in an
office, university, or café.

Many Internet companies use these examples to claim the IP addresses
are not personally identifiable, that they are just broad
representations. But while IP addresses do not always identify
households, they do so in a significant percentage of traffic
(especially in Internet traffic outside work hours).

Of course, there are legitimate and even valuable uses of IP address
tracking. Tracking the IP address of suspicious ad clicking behavior
often helps prevent unsophisticated hackers from committing click fraud.
Using an IP address as an additional piece of identity allows an
efficient way of spotting when a credit card or identity has been
stolen. IP addresses can help understand the country of a user so you
can customize the language displayed. However, in the process of
providing valuable services to its customers, many Internet companies
are needlessly tracking a wide variety of data in their logs correlated
directly to the IP address.

Cookies are safer for consumers

Fortunately, for companies interested in tracking user behavior for
Internet personalization, there is a great consumer-centric alternative –
the cookie. Using cookies to track users and provide valuable services
has several important advantages over using IP addresses:

  • Because cookies sit as plaintext on a user’s browser, they identify
    the party tracking user information clearly.
  • Since cookies are governed by browser security preferences, the user
    has complete control over the amount of tracking and can choose between
    anonymity or personalization. Another benefit is that cookies can be
    cleared easily and at any time (unlike IP addresses).
  • Cookies can only be tied to one browser in one device (unlike an IP
    address, which is tied to all devices in a household). Most
    importantly, third party cookies should not include any personally
    identifiable information. If used properly, cookies allow Internet
    services to improve their products and the consumer experience without
    fear of compromising an individual’s anonymity.

Despite these advantages, awareness of what cookies are and how they
work continues to be a challenge for the average consumer. Nonetheless,
cookies represent the best technical compromise between personalization
and a user’s control over online identity.

The IP address should be considered protected information. As such,
we should agree on a certain limited set of circumstances (e.g. fraud
prevention) in which IP address tracking is necessary. Even for these
circumstances, we should agree that anyone collecting IP addresses
should be held to a higher standard of security and consumer disclosure.
For the vast majority of Internet personalization cases, we should
eliminate tracking of IP addresses and move more to a cookie-centric
world in order to protect Internet users and promote more responsible
growth and innovation.

5 thoughts on “Why IP Tracking Is A Bad Idea

  1. Alisongreen25@comcast.net

    Auren, this will probably mark me as incredibly naive, but I always thought that IP addresses just identified you by rough geographic location (like city). Are you saying they can in some cases link to your home address? Are you able to explain further or link to an article that does? Thanks!

  2. Robert

    Hi Auren,
    another great blogpost – wondering why it’s got so little comments. In fact @ Criteo, we do exactly that: store all information on a cookie. if you don’t want to have it, you can delete or block it – which is a huge quantumleap for privacy in comparison to what others do, who regularly crawl the content of your private mails / friends or other data… which you can never switch off without stopping to use vital services on the net.

  3. Auren Hoffman

    Alison — an IP address sometimes can uniquely identify a home or business address. about 30% of U.S. households have a static IP — meaning that the IP does not change. that means that if you have a static IP and a site links you to the IP, you cannot ever be anonymous to that site.
    today you can buy lists of IP addresses linked to names and addresses — so it is easy for any site to acquire if they want to track someone. I strongly feel this is wrong and sites/ad networks/widgets/etc. should not do it.

  4. Simo

    Interestingly, RFC3041 defines privacy extensions for IPv6, which could stand to eliminate some of the concerns with IP address by allowing a client machine to randomize portions of their global address.
    It remains to be seen how and when IPv6 will become a player in the global Internet. IPv4 address exhaustion has been an imminent problem for years already, and most operating systems fully support IPv6, but the movement to change has been quite slow.

  5. Gregg Hamilton

    Thoughtful, informed, compelling post. I suspect that it is only a matter of time before Congress takes a more forceful position with respect to online privacy than currently exists in the US. I think that legitimate direct marketers AND consumers both ultimately benefited from the Do Not Call and Can Spam legislation, but I am fearful that a tipping point privacy violation could provoke stricter reactive legislation than is really necessary.


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