A Microsoft technology for Windows XP that was under attack recently were the so-called “smart tags”. MS would insert links into any web page you would browse, that would allow you to access “relevant information”. Obviously, this is quite controversal, as the creator of the web page has nothing to say about the links Microsoft would insert into their page.
SmartTags are off for now, but don’t hold your breath – other companies are rushing into this space! Click on the above link for details.