Ajax is good at displaying different content in the same url. There is no way for search engines to index pages like that. What search engines need are unique urls. No matter how long the url, as long as they are unique, it is all good.
I heard there were some development in making search engines read ajax code… in the mean time, i dont think it will work after doing some experiments in a few websites.Â TheÂ inabilityÂ for search engines toÂ follow ajax hyperlinksÂ is a major disadvantage to Web 2.0.