Joel on Google Suggest

The latency of web UIs, in which everything you do is a slow round-trip that requires completely refetching and rebuilding the web page, is one of the reason web UIs feel so clunky compared to native GUIs. Google is very publicly raising the bar on the quality of interfaces that people will expect from web pages.

http://www.joelonsoftware.com/items/2004/12/10.html