I too don't actually see it via copying like the article mentions... however a quick View Source on this and another Posterous blog does reveal some javascript

I too don't actually see it via copying like the article mentions... however a quick View Source on this and another Posterous blog does reveal some javascript to call these guys: http://www.viglink.com/ http://www.viglink.com/ Pretty neat, I think! Assuming they're not overwriting existing affiliate URLs, then this seems like a reasonable game to play. In my mind, Posterous is providing free hosting / platform for the blog, so they have at least some claim to having helped make the affiliate sale. This isn't going nearly as far in bending the rules on affiliate programs as Browsarity (another YC company): http://www.browsarity.com/about.php http://www.browsarity.com/about.php (And good for Browsarity -- but I'm still surprised that various affiliate programs haven't disconnected them yet because of their much more tenuous connection to the underlying transaction.) [EDIT: clarifed this last sentence]