This is the best answer for your query... Google takes a snapshot of each page it examines and caches (stores) that version as a back-up. The cached version is what Google uses to judge if a page is a good match for your query. Practically every search result includes a Cached link. Clicking on that link takes you to the Google cached version of that web page, instead of the current version of the page. This is useful if the original page is unavailable because of: * Internet congestion * A down, overloaded, or just slow website * The owner’s recently removing the page from the Web
Google Cache is a feature of Google where copies of web pages are stored. Only text pages are stored, no images or other binaries are cached. It's a kind of temporary archive. Thus, when you send a search query to Google, web page matching your search keywords are retrieved locally from the cache on Google's servers. This feature improves speed for fetching pages, and cached copies of pages can be viewed even if the original page has been deleted or not available due to some technical reasons.
Here's a helpful link for that question http://www.googleguide.com/cached_pages.html and so is for other google related search engine optimization
when google will crewel your webpage is called cache process which you can know by cache link at google result
A cache (pronounced CASH) is a place to store something temporarily. The files you automatically request by looking at a Web page are stored on your hard disk in a cache subdirectory under the directory for your browser (for example, Internet Explorer). When you return to a page you've recently looked at, the browser can get it from the cache rather than the original server, saving you time and the network the burden of some additional traffic. for more you go here: searchstorage.techtarget.com/sDefinition/0,,sid5_gci211728,00.html