if one needs a perspective on the possibilities this new feature may spawn, look no further than the AOL leak a few years ago. and some more. --- where these searches were recorded only after hitting the GO button, as AQ points out below, google-instant gives you the flexibility to damn yourself for not learning to type accurately. and one day some idiot leaks the search results (along with the thought-crimes) for the whole world to see. and then you wish your life had gone down the memory-hole. alas!
i like to be able to type in my desired search term before being given any results/suggestions that's all. one thing that comes out of this feature is that it confirms the lingering suspicion born with the advent of the internet - that "they" know what we're doing with our computers the very second we punch in a key - contrary to popular belief that "they" will know what we're doing only when we hit the "enter" key or click on "submit" or "send mail" or "save" who's to say this technology isn't applied to read our personal emails, calendars and so forth? you're essentially doing the same thing in an email editor what you do in a search engine's search bar. even if the suspicion was false in the past, we now know that such technology is available henceforth. not that we have anything to worry about as long as we're clean, which we are. however, welcome to a new age of thought control, subliminal messaging, psychological programming, social engineering, and illegitimate policing of citizens - if it hadn't begun already. makes one reminiscent of the days of the cold war and the KGB. or it could just be me.
It's pretty impressive in my opinion. mobile version(to be released soon) will be really time saving.