Last month Google rolled out its Instant Search feature and now the company is testing a full page preview feature that shows a preview of the website when you hover over the search result.
Many have been unable to reproduce this. Including myself, but sites like the TheNextWeb are reporting that this is indeed happening, so this likely isn’t a hoax. This is different than the thumbnail previews that Google introduced a year ago as a search option (available in the left hand options bar). This iteration of the page preview shows a full size representation of the site with more detail and visibility.