Google has come up with a set of guidlines to make Ajax applications Searchable.  This was a major limitations for the Ajax applications.

While AJAX-based websites are popular with users, search engines traditionally are not able to access any of the content on them. The last time we checked, almost 70% of the websites we know about use JavaScript in some form or another. Of course, most of that JavaScript is not AJAX, but the better that search engines could crawl and index AJAX, the more that developers could add richer features to their websites and still show up in search engines.

Read more about the this at google webmasters blog.

They say the best design is the simplest design.

Google’s proposal seems rather complicated. If that is the case with a technical person like me not sure how is it going to fare with other folks.Plus this approach has to get the blessings of other search engine.

Whats missing is a reference implementation. Google should definitely make one so that we can understand this better.