Cache What is a Cache ? According to en.wikipedia.org, a cache is simply a temporary storage area where frequently accessed data can be stored for rapid access. After these data have been stored in the Google's cache, they can be accessed easily (called the cached copy, or cached version) for future purposes.
If you want to visit a site but you receive a 404 Error message (below is a sample), the best action to do is search for that site on Google by typing the cache:operator and the link.
Below is an example of a cached page which is retrieved by typing cache: www.mytravelguide.com/restaurants/strestaurants-206401-Belgium_restaurants.html on Google. link Date cached
Why Cache? <ul><li>if an HKA is unable to access the page containing the information he/she needs </li></ul><ul><li>solves the problem of TLs and TLAs who can't retrieve or check data because the web page is down (404 error)
helps them locate information which has been updated, revised, or removed from its website </li></ul>
How about retrieving multiple copies of older versions? Unfortunately, Google only caches single copies of webpages, same as with Yahoo!, Ask, Live, Gigablast, etc. It means that if you want to find older versions of a particular website, you cannot be assisted by Google (and others) because it only stores the latest cached version of that webpage. However, there are some sources that contain archives of different websites with their corresponding date to give you an idea how old those archived pages are. One of these web archives is the Wayback Machine .
http://www.archive.org/web/web.php “ Launched in October, the Wayback Machine is the public's access point to contents of the Internet Archive, which has been cataloguing webpages since 1996, and has given itself the goal of preserving -- among other things -- the 'entire publicly available web'." Per http://www.csmonitor.com/2001/1113/p25s1-stin.html An example of Wayback Machine's page displaying http://news.bbc.co.uk/'s pages from Dec 12, 1998 -Apr 1, 2008 ( Material typically becomes available 6 months after collection).