gistfile1.html

<!--
Below is the exact code snippet IDG are recommending their clients to put on 
every page of their site to enable retargeting.

Including quotes around the whole thing, which lots and lots 
of people will add too.

Note: {NNNN} placeholders represent identifying numbers, 
which I have removed and replaced with the {NNNN} parts in this example.
-->

"<script type='text/javascript'>
var axel = Math.random() + '';
var a = axel * 10000000000000;
document.write('<img src=""http://pubads.g.doubleclick.net/activity;dc_iu=/{NNNN}/DFPAudiencePixel;ord=' + a + ';dc_seg={NNNNNNNN}?"" width=1 height=1 border=0/>');
</script>
<noscript>
<img src=""http://pubads.g.doubleclick.net/activity;dc_iu=/{NNNN}/DFPAudiencePixel;ord=1;dc_seg={NNNNNNNN}?"" width=1 height=1 border=0/>
</noscript>"

<!--
So, to sum up:
1. Creating a global variable (!) named "axel". A random number between 0 and 1. 
   Coerced into a String, by concatenation. 
   WTF?
   Global variables are generally something to be avoided. Will overwrite anything else already occupying that name.
2. Creating a global variable (!) named "a". Set to the value of "axel", multiplied by a very large number, 
   coercing it back to a Number (but still with decimal points, I think.)... WTF?
   See point 1.
3. document.write. Ugh.
4. Note the double quotes in front of (and after) the src-attribute. Whoops.
5 ...in both the script and the noscript versions.

-->

I approve of these design patterns!