This especially comes in handy if you’re looking for a Web site that is no longer there (for whatever reason), or if the Web site you’re looking for is down due to an unusually high volume of traffic.
Here’s an example of how you would use the cache command:
cache:www.websearch.about.com “web search”
You’ve just asked Google to return the cached copy of the About Web Search page with the words “web search” (remember the quotation marks? That means you’ll see them in exactly that order on the page) highlighted.
Conversely, almost every site you come across while using Google will have the option of accessing the cached version right there in the search result. Clicking on “cached” will bring you immediately to the last copy Google made of that particular page.