Clearly AJAX improves the user interface but does this also decrease server load?  You would think it does because the entire page will not have to be served up each time, but maybe there are other variables I'm not considering.  
Would using AJAX extensively improve server performance?
performance;ajax
It depends on what you're doing and how you're doing it.If you're replacing full page loads with AJAX requests (i.e. onlydoing AJAX calls when a user clicks on what would have been a fullpage load) then AJAX will decrease server load because you're(presumably) doing less processing and returning less data.On the otherhand, if you're adding auto-update type AJAX that pollsthe server every few seconds then that could increase loaddepending on the user (it might not increase the server load if theuser keeps hitting F5 to refresh manually anyway, but most peoplegenerally don't do that for hours)Another AJAX optimization is to only load more data as you scroll. In that case if the user doesn't scroll all the way down, that'swasted processing.Of course actually implementation can skew results either way, these are typical results assuming reasonably good implementations.