Search engine such as Google keeps a cached version of every web page when its search bot crawls the page for its search index. The cached version is handy if the page that you used to visit is no longer available. Or the web server is under high load that it has problem serving you the page.
To get the cached page from Google, enter this inside Google search:
For example to view the cached version of MacBook page at http://www.apple.com/macbook/, enter:
This query will redirect you to a page under Google at webcache.googleusercontent.com.
On the top of the page is a banner indicating it is a Google cached version, with a timestamp when Google bot took the snapshot of the page.