Livesearch was an experiment in creating an alternative search experience that intuitively predicts the most likely search query based on what the user is typing. Using Ajax, the suggestions update in real time as the user types. Based on the most likely suggestions, the corresponding results are pre-fetched even before the user submits their query.
Livesearch is very useful as a research tool to explore a concept space, and can be eerily accurate at predicting what a user is looking for.
Sadly, Livesearch, which was hosted on alltheweb.com, saw end of life at the end of 2007.