Its most prominent use currently is with Google Suggest. There are several places in HelpSpot where this technology would be a great use. It could potentially make parts of the system like the inbound request queue extremely dynamic and completely real time.
My hesitation in using this is that unlike Google’s use of the technology, mine is part of a larger system. In Google’s case the technology is used on the one form the site has. In HelpSpot there are many many forms, data tables, etc. In most parts of the system using XMLHttpRequest would make no sense. So the question is does the benefits of using it in a few parts of HelpSpot outweigh the significant downside of creating alternate user experiences in different parts of the same application?
I don’t know.