Currently, a small ajax web app of mine uses an anchor hijacking method to display content. The user clicks an anchor, I cancel the default browser event and funnel the link into an AJAX call, after which I retrieve content and insert/animate it in.
HTML snapshots, where I reprogram the application to work with the browser and have it serve up a version of the site for each bit of content, so essentially instead of seeing the barebones content everytime google requests a link it would see a version of what the content + code would look like had a user carried out that operation.
The problem is the latter is fiddly and annoying to reprogram, an I'd like to see if there's any significant improvement in SEO that would warrant the extra time and money spent to reprogram it.
Link to the article on making your AJAX web application crawlable for reference.