(2005-10-17) Ajax Popup

I've been thinking that one good use of AJAX is to populate little Pop Up windows with dynamic info, so you can get extra info around a link/entity (e.g. list of Sister Sites matches) without loading a new page.... on the other hand, if you're going to open a popup and wait for the server info anyway, is it really going to be any slower to just do a pre-AJAX popup? I'm probably being an idiot...