There may be instances you do not want people to access your cached content, and can remove it. We had a client whose site had been hacked and stuffed with spammy content about prescription drugs.
They updated their site, but Google still showed the spammy text in the cached page link. Google will remove the snippet and cached page from search results, although the title and URL of the page will still be visible. Caching improves and speeds up browsing. Once you've downloaded an asset, it lives for a time on your machine.
Retrieving files from your hard drive will always be faster than retrieving them from a remote server, no matter how fast your Internet connection. Take a typical ecommerce site. Certain assets, such as the logo, will appear on every page in the exact same location no matter where you are on the site. Without caching, your machine would have to download that logo every time you clicked on a new product page. Along with large images, complex sites use large JavaScript files - necessary for applications such as shopping carts, interactive images and wish lists.
Imagine how conversion rates would be negatively impacted if a user had to wait five to ten seconds for a "Buy Now" button to appear beneath a product. A fast, fluid browsing experience is essential to making customers feel comfortable and encourage conversions. In addition, the next time you visit the cached ecommerce site, those assets will still be available on your device for faster loading.
Mobile devices are frequently limited by bandwidth. Some mobile data plans also have bandwidth caps or charges. The less a user has to download of a website, the better for them. You've enabled asset caching for your website. The next day, you decide to change the color of your logo. You swap out the old logo for the new one and check your live website to see how it looks. But the old logo is still there. Your machine has a cached version of your logo on the hard drive. It never bothers to request a new download of the image.
Without any type of caching, whenever you visit that page you make those requests all over again. And every other person visiting that web page is making the same requests. If there are lots of people accessing a page at one time, the server slows down and takes longer to deliver the web page to everyone. Caching solves this problem by storing a copy of the assembled web page in a couple of different locations.
One way to cache content is to do it directly on the hard disk of your personal computer. For example, a website logo is often repeated on each web page. Web pages are also sometimes cached closer to the website server, rather than on your personal computer. When a website installs a cache on top of their server, they are keeping copies of the relevant files and instructions in that cache.
The website can control how often their cached content needs to be updated: if you are the first visitor to a web page after the cached content has expired, the cache will re-collect a new version of the web page from the server, then deliver that content to you and save it until that newer copy also expires.
This graphic illustrates how it all works:. The higher the cache hit percentage, the more often people are getting content delivered to them through the cache, meaning web pages are loading faster for them and there are less requests going to the website server, which also decreases server hosting costs for the website.
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