I wrote some articles lately on using a Cache Component for your Joomla based website.
Now why do you want to use caching if you are Optimizing your website for Search Engines?
The thing is that most Content Management Systems are using a database, mostly MySql, to hold their content.
To display this content there is a “simple” process that creates the page in you web browser that takes you Template file, selects the content that is requested by the browser from the Database and gives it altogether to browser to display it to you visitor.
This process is called “parsing” that is done by your web server of choice, for the most hosting providers this will be Apache, some will use IIS from Microsoft.
Content Management System will be based on PHP, ASP or other more proprietary systems.
But what all of these systems have in common is it that your web-page is generated “On the Fly”, that is when it is requested…
A Search Engine Robots view
Have you ever watched your statistics to look at how much time a search engine spider spend on your website?
Please do, you will be surprised at the time it spends. The come and go on my websites under a second !
I wrote some time ago about How Your hosting provider helps you with SEO and talked about the standard cache functions of Joomla.
Having a Cached version of your Webpages helps search engine spiders to fetch that already made page and read it faster then if it still has to be created.
Now that is logical, right? Yes it is!
So caching is a function you should use if its available for your Content Management System.
Lately there is a new component for Joomla that is working much better than the standard, at least for Not Logged in users. I don't now any Search Engine Spiders that Login to a web-page (Unless its the depot of the Home-base where it must Unload its content :-))
You can read more about the features and installation at “How to boost you Joomla performance”
Drawbacks of Caching
It's not all Golden if you start using caching.
Depending on the caching system of choice you might have a system that uses files or one that uses Cache tables.
But in all cases you need to set the caching time.
Caching Time means the time, in seconds, that the generated page is staying in the cache before it is removed.
You need to clean out your cache sometimes, other wise new page content stays in the database and will not be shown…
This time should reflect the update time of the content of your website, so a news site hast to have a shorter “time to live” for your caching system than a semi static website.
You also need to have extra space on you server to hold the cached files, sometimes this can be more than expected, especially for large websites with lots of content.
But hey, these are the ones that will gain the most of this system, since it will free up resources from there web server CPU time to work more efficiently.
So its a small price to pay, then space is not an issue anymore for most hosting providers.
For some systems Caching is still under development like finding the right system for Drupal is not that easy.
For Joomla your best choice is the default completed with either the Components of Joomlatwork (Commercial) or IrcMaxell
If you use WordPress, like this Blog, you could use the WP-Cache Plugin.
Just a word of advice, Clean your cache after writing or changing the content of your website !