Instead of actually doing the diff process on the client or server side, this may be useful as a method of returning Javascript events and transformations from the server side to the client side for rendering; i.e., instead of returning script fragments, or JSON detailing the data itself, as the result of an Ajax call to the server, the server script would return an abstract set of "changes" to perform in the DOM, potentially along with other data. Sort of a server-side "DOM diff" structured with JSON, allowing a higher level of description than just spurting out some Javascript or an array of data.

Wow, that was way too many tacky web 2.0 terms for one paragraph.. forgive me.