By Jack Schofield, The Guardian
Some websites now use software that can identify visitors by name,
using tracking cookies (small text files websites store on your hard
drive), internet addresses, and forms filled in at other sites. (See,
for example, You’re not anonymous. I know your name, email, and company, and Nowhere to hide: Advertisers can now stalk you across multiple devices.)
is the web’s biggest advertising company and one of the most obvious
trackers. It uses a huge network of ads that are shown across millions
of websites, DoubleClick ad-tracking, the Play marketplace on Android
phones and Google Search on Apple iOS devices – unless you opt out.
It also looks as though the main purpose of its Google Plus website is
to get users’ real names and other accurate data, which Facebook has but
won’t provide to Google.
Facebook has also extended itself across
much of the web using Facebook Connect and Like buttons. Users can log
on to participating sites using their Facebook identity, and this gives
these sites access to some information from their Facebook profiles.
This is handy but less private than using different IDs for different
sites, or using throwaway IDs and passwords from Bug Me Not.
The latest Web Privacy Census
by the UC Berkeley Center for Law and Technology found the most popular
100 websites dropped thousands of cookies (6,485 on 24 October), and
that 84.7% of them were third-party cookies. In other words, most
cookies were not used by the site you visited (Amazon, Twitter etc) but
by advertising and tracking companies such as Google’s doubleclick.net
(the biggest, dropping 69 cookies), scorecardresearch.com (54), and
So yes, there’s a whole host of “automated
watchers” waiting to see if you use Amazon/your bank/hotel booking sites
etc, and they may “spam” you with targeted advertising or perhaps
legitimate email offers. (The companies argue that it is better to show
you ads about things you are interested in, and they have a point.)
Given that there are several hundred tracking companies, it would be
surprising if there wasn’t some “leakage” into less legitimate
approaches, though I’ve not seen any evidence of this happening.
However, hacking is always a possibility.