Since Google released instant search, I have been seeing different variations pop up everywhere.I am wondering what is the special ingredient making it happen. Or is there more than one way?
This just popped into my head, might be terribly wrong, but I would just do ajax. Like the way you implement autocomplete by listening to keyup events and returning stuff to fill the list of results. The thing is that this should be wicked fast to be instant, so some optimizations with load balancing and cache related things must be going on there as well.
I did a flickr instant image search http://instantimg.appspot.com/flickr basically, using ajax and the flickr api, on keyup I search whats on the input box and display it