I think they've found a very complicated solution. Wouldn't it be much much easier to:
1. give the content behind the ajax call a static url, which can be accessed by non-js clients too
2. add something like <link rel="alternate" media="ajax" type="text/html" href="http://example.com/doc.html#state /> to the head of that static version, which the search engines can then use as a pointer to back the js version
1. give the content behind the ajax call a static url, which can be accessed by non-js clients too
2. add something like <link rel="alternate" media="ajax" type="text/html" href="http://example.com/doc.html#state /> to the head of that static version, which the search engines can then use as a pointer to back the js version