I agree with my friend at problogdesign that Ajax can be a good technology to work with and it seems to have changed the face of web world since there is no need to refresh the page. He says that if used properly it can work wonders and I would say that anything done within limits is always fine. Further he talks about how Ajax could be implemented in your blogs. Here are the five areas where it can work well:

Commenting
Editing comments
Comment preview
Voting in polls
Rating systems




One more thing Ajax has even changed the concept of analytics to such an extent that soon page views will lose its position as an indicator of popularity of a website. I think as its replacement the amount of time spent on a particular blog could be a good pointer regarding how well a blog is performing but this concept may not work as well for other websites.