Yahoo announced Instant Search last night (more info on this landing page).
Like Google Suggest and Snap, Yahoo has added ajax functionality to search.
It’s different, though. Google Suggest and Snap use ajax to suggest search queries based on what you’ve typed in so far, whereas Yahoo has integrated basic search results into the interface. This means you can get answers to simple and popular searches (like weather) without a page refresh.
Try it out. Yahoo suggests queries such as “Boston Weather” and “Wikipedia”. This type of search gives good results.
And Yahoo takes a small swipe at Google by saying ““Why feel lucky when you can be right”, a reference to Google’s Feeling Lucky button. John Battelle says “Meeeeyowww, the claws are out….” 
Additional Reading
Charlene Li, Google Blogoscoped, Brad Hill, Ken Leebow, Search Engine Roundtable
Oh, that’s actually hot. I definately like this a lot better than Google Suggest. Never thought I’d actually like a Yahoo service (Flickr doesn’t count). Still sticking with Google’s personalized page as my homepage though. Although… I do have that copy of GoogleX (boohoo @ it’s official demise) sticking around that I’ve been wanting to start running on localhost… I should get around to doing that.
It’s a cool little hack, but I’m not sure how useful this kind of interface will be. On my (slow) laptop, it takes as long or longer to get “instant” results than it does to do a normal search.
Also, having only one result can make for some “interesting” suggestions. A search for “DE” (the ISO code for Germany) brings up Google(!) Germany as the “best” result (screenshot on my blog).
This looks like yet another toy by Yahoo only to generate buzz because no one is likely to actually use it.
I mean, what is the purpose of showing an irrelevant result 9/10 times after every letter your type on your way to what you’re actually looking for? What motivation for regular folks is there to use this kind of service instead of standard search? I don’t see any just like with Google Suggest.
This web-site is the coolest! Now I don’t have to feel so intimated by science! You’re a genius! I think I’ll visit this site oftenc
Very interesting design.. I’ll come back to see updates.r
Anyone know how I could put instant search on my site?
faaakinewll i jus wanted 2 get 0n de syt kidah but u wnt even lemme on get me gang u deserve shuttin dwn im guun try yh n if it wnt letme im gna kiwl yo cat mayne … ya herd meh :D:D:@:@:s:s::(:( …..mixed emotinons blad
How did u do this! It’s perfect! the best site i’ve ever seen.A