Web 2 (point) Uh-Oh and SEO
Ajax, that powerful programming language gives developers the ability to improve the user-experience of their website with dynamic pages that act as web applications. The problem for those sites which utilize Ajax however (just like Flash) is that they are difficult to index for search engines. If you have an Ajax enabled site there is a good writeup on the subject over at the Google Webmaster Central Blog which should solve most, if not all, problems related to Ajax and SEO.
If you're starting from scratch, one good approach is to build your site's structure and navigation using only HTML. Then, once you have the site's pages, links, and content in place, you can spice up the appearance and interface with Ajax. Googlebot will be happy looking at the HTML, while users with modern browsers can enjoy your Ajax bonuses.
According to the GWC Blog: "Note that the static link's URL has a parameter (?foo=32) instead of a fragment (#foo=32), which is used by the Ajax code. This is important, as search engines understand URL parameters but often ignore fragments."