title: What's your favorite cross domain cookie sharing approach?
body: <p>I see iframe/p3p trick is the most popular one around, but I personally don't like it because javascript + hidden fields + frame really make it look like a hack job. I've also come across a master-slave approach using web service to communicate (<a href="http://www.15seconds.com/issue/971108.htm" rel="noreferrer">http://www.15seconds.com/issue/971108.htm</a>) and it seems better because it's transparent to the user and it's robust against different browsers. </p>
  
  <p>Is there any better approaches, and what are the pros and cons of each?</p>