Thank you for your email. We greatly appreciate any feedback or suggestions for ways we can improve Google Analytics.
Please note that I have informed the concerned team about the error in the documentation. As you mentioned, the article is incorrect:
onclick="_gaq.push(['_link', 'http://www.firstsite.com']); return false;">Login Now</a>
It should be:
'https://www.secondsite.com/?login=parameters']); return false;">Login Now</a>
Thanks for bringing this to our attention. Please note that this documentation will soon be edited.
If you have additional questions, please visit our Help Center at http://adwords.google.com/support/aw/, where you'll find answers to many frequently asked questions. We look forward to providing you with the most effective advertising available.
The Google AdWords Team
been having trouble with cross domain tracking issues - turns out that the documentation on the google site was wrong... classic. This was the response from the big G: