Adwords's Conversion Tracking, why it works?

Do you ever consider why it can read your cookie from 3rd party website?

[iProgram]

Hi all, let me describe how it works:
1. A customer clicked your AdWords, google put a cookie to customer's computer. For example:
Cookie Name: AdWords
Cookie Value: 1234

2. This customer ordered your product and came to "Thank you for your ordering" page, which uses Google's Conversion Tracking.

3. G's Conversion Tracking uses its JavaScript to display an image: <a href="http://www.googleadservice.com....."><img src="http://www.googleadservice.com/some-script-to-read-cookie"></a>

In theory, this script can read the cookie set by google itself. However, the default IE privacy does not allow that at all (IE Options->Privacy). It does not allow a script of googleadservice.com to read a cookie set by googleadservice.com itself, when that script is loading by another domain's page (the "Thank you for your ordering page"). Isn't it?

[roitracker]

Not quite sure what your question is, but you are correct that your browser will consider it a 3rd party cookie.

[blaze]

I believe Google has set a compact privacy policy on the image/cookie. IE will allow such 3rd party cookies.

[iProgram]

compact privacy policy? How can I set this type of cookie?

[roitracker]

IE6 requires a P3P privacy policy before it will accept 3rd party cookies. The cookie itself is not different from any other cookie - compact P3P is just a way to tell the browser what type of data will be stored in a cookie before the cookie is actually set.

You can find out more about P3P at: [w3.org...]