An ever increasing number of web apps are utilizing AJAX to deliver an addictive user experience. Here's a list of apps/mash-ups I like that leverage AJAX -
* YouTube Instant Messaging - developed by Stanford University student, Feross Aboukhadijeh, this is a predictive search results feature for YouTube that is inspired from Google Instant. This has in turn inspired Google Maps Instant.
* Google Scribe - This Google Labs product provides autocomplete suggestions while you type, like the free desktop tool PhraseExpress After you install & activate the Scribe bookmarklet, it will start offering suggestions to complete sentences whenever you type within textareas or textboxes in any site.
work in progress...