Gizmodo dig out an interesting post on the "instant" Live Search interface created a year ago by Long Zheng, in his spare time -- dubbed "Real Live Search" using Bing's AJAX APIs.
Zheng wrote it back in in 2009, but Microsoft's got all excited about it this week. Bing's director Stefan Weitz has even spoken to USA Today about it—noting that "Google Instant" interface itself isn't anything new. There was a site put up last year that does same thing with Bing APIs." Then he talks some smack about how Bing is a "decision engine" and while speed and fewer clicks are all very good from a user convenience point of view, but the real game is "not about giving you much more links faster, it really is about getting you the information you need to make a decision faster in the format that makes the most sense." Stefan blithely ignores all the thinking about how much of a boost this'll give to online advert trade, but at least he does acknowledge that "speed is important."
Weitz also acknowledges Google's genius in Instant was in being able to scale up the real-time search (using various predictive tricks) to provide the boosted service to millions of users without blowing up its server farms with the added burden.