For some time, Google has had a feature that allows you to search for a term and automatically be redirected to the top scoring page. It's called "I feel lucky." I don't know how often it is used, but I'd guess often enough for Google to keep it there on the default search page.
In an effort to speed up browsing, Google is implementing "prefetching" of top search results. They'll put in a link that is, in effect, a command to your browser that it should go and retrieve the top result in the background so it'll already be loaded if you click on it. Sounds convenient. But it has more than a few SlashDotters worried. To anyone reviewing your cache or looking at your network connection (such as a sysadmin), it looks as though you manually surfed to that page which may not reflect well upon you. It will really depend upon what you search for, but there are a number of other unpleasant possibilities of this "feature". Anybody can capriciously put tags into their pages and have completely unknown pages loaded onto your computer. I could put this on my page "<link rel="prefetch" href="http://www.someplacenasty.com/">" and whoever reviews the firewall logs at your workplace will think you're up to no good. Or I could prefetch a link to an advertiser from my site so it'll look like every visitor has clicked on an ad, putting pennies in my pocket.
The "prefetch" function is enabled by default in Mozilla browsers such as FireFox. I don't think that IE has this feature, but it may in future versions. Users would be sensible to disable it.