Once you have Google Instant Previews enabled, you'll see a small magnifying glass to the right of every Google search result (). To start using Instant Previews, you simply click on one of those icons. You can also hit the right arrow key if you prefer a mouseless navigation experience.

Whichever way you do it, activating the magnifying glass brings up a preview thumbnail for the page in question. It doesn't take long, either; Google says it's usually a delay of less than one-tenth of a second. Despite my best speed-counting efforts, I couldn't quite tell if that estimation was precise -- but let's just say it was pretty darn close.

Each "instant" preview shows you a current view of the page, complete with text, graphics, and anything else that might be present (). If you click on the thumbnail, Google takes you to the site. If you move your mouse anywhere else within the search results, Google starts loading previews for other pages in the list.

When Google detects text that seems particularly relevant to your search, it creates an orange-highlighted pop-out box within the preview so you can read the words (). When I searched for "Conan O'Brien review," for example, Google Instant Previews pulled out text showing a review of Conan's first show from People.com.