Google's new personalised search now works even if you;re not logged in. I never used personalised search before and found it highly annoying, so I haven't been looking forward to the public one. You don't really have much of a choice to opt-in - you're co-opted in automatically just by using Google (which on principle I really hate). You have to opt-out (repeatedly even) - so there's no respect for your personal wishes.
Here's my big question: if you always got back the same results from the same sites you already know of - what do you need Google for? I'm guessing the impact of this will be low and that it may even be pulled/easier to opt out of than it currently is.
One of the first times we came across personal search issues was shortly after it was launched more broadly sometime last year. A friend of ours in Dublin was doing a demo and discussing SEO with a client of theirs. The client wanted to check where we ranked but we didn't show up anywhere. My friend rang me and they were quite curious - we eventually clicked that they were logged into Google and they were seeing personalised search. And it's been a big problem since then, so I'm wondering how much of a problem will it be going forward.
A couple of people have raised the idea that Google may be doing this to push their own AdWords sales and to be honest, I'm wondering myself.
Initial Verdict: Google may be a very successful search engine - but thats because they were so clever and user focused at the start. Now they're changing quite radically. If open personalised search is the future and in the best interest of the user - then I can only agree with it. But I'm still not so sure....watch this space!
Google's Official Blogpost