Google took a big step from generic search to customized and personalized one with the announcement of Official Google Blog: Personalized Search for everyone. Do we like personal attention? Sure! What's the price? Privacy. Since technology is relying on tracking user behavior from cookies embedded by Google. Privacy advocates, I am sure, will be furious over the "big brother" watching every step and move. As for me, I think, privacy battle is lost for general Internet user. Those who care should be using anonymizer software and other tricks and tools.
So what's next? I think - personalized recommendations. Google is sitting on the top of goldmine of ratings and reviews crawled from the Web, extracted and normalized from RDF and microformats (http://googlewebmastercentral.blogspot.com/2009/05/introducing-rich-snippets.html). And that will be a huge step for the giant - whoever can tinker with recommendations can control user buying behavior. And as you can guess, how much money is behind that... Advertising market will be a part of a bigger "user behavior control" market not too far in the future.