Google had launched instant previews back in Nov 9 2009 but sadly this feature has been removed.
Why Did Google Remove Instant Previews?
Google has removed the instant preview feature because users were not taking it seriously and Google saw a low usage rate of this feature among its users.
What’s New?
The new search result pages will show the cached and share feature under a small green drop down button displayed under right hand side of the website titles displayed on the search results.
Also See:-
Google Ranking Fluctuations
Google Change History Feature in Google Analytics
Google Tag Manager
How to Make Full Use of Google Authorship Profile
PageRank Dissipation between 301 Redirects and Normal Links
Google to Take Action Against Sites that Sell PageRank
Search Engine Optimization or Search Experience Optimization
Google to Extend Support to Toolbar PageRank