Google and other search engines cache pages, storing copies of them that they use for indexing. You can think of the cache as a snapshot of a page at a moment in time.
You can examine the cached copy of a particular page by creating a query like this:
You can look at any page by placing it immediately after “cache:”. You will then see the time and date at which Google stored the cached copy as well as how the page appears to Google.
The purposes of inspecting the cache include the following:
* If a page is in the cache, then the search engine has been able to find it and has indexed it.
* You can see how recently Google has taken a snapshot of that page and thus get an idea of how likely it is that recent updates have been “noticed.”
Some important caveats about the cache:
* Just because a page is cached doesn’t mean it’s easy to find or going to rank well.
* It takes time for some pages to be found and cached. A page that isn’t present may be too new for Google to have found and cached. However, if you know your site is frequently visited by Google and hasn’t been cached in a reasonable period of time (several weeks), make sure your links to that page can be found and followed by search engines.
* There is a (considerable) delay between content updates, caching, indexing, and PageRank changes. The date of the cached copy does not mean that the search rankings or PageRank values reflect that version of the content. There is always a lag.
* Just because you see it in the cache doesn’t mean that the search engines are reading it exactly as you would expect. Google — and other search engines — purposefully are vague about how they actually look at and rank pages so that it’s hard to take advantage of their algorithms. The cache may draw images from your current web server.
* A page may be found by Google in various ways. Someone else may have linked to it in order for Google to find it. Presence of a cache doesn’t mean that you have a great navigation scheme.
Note that almost all of the above information applies to the other major search engines.