For any website administrator, having a content version history is an important asset. For Joomla, until recently, you had to find and install a third party add-on. But not anymore, finally content versioning is part of Joomla since Joomla 3.2.
If you are starting a new site with Joomla 3.2 this feature is enabled by default. If you are upgrading from an older version, is there, but switched off.
You need to enable it by going into Article Manager, and select Options. On the Editing Layout tab you will find a new option, called Save History. Switch it ON, adjust the Maximum Versions setting to your preference. This sets the number of latest revisions to save for the article.
When done, Save & Close the Options.
Now you can test if works!
For example add a new article, add some content to it, then save it. Do some edit, and save it again. Make a few more revisions, then click save again. Finally, click on the new Versions button on the top to see the saved changes.
If everything is working in the opening pop-up you will see a list of the timestamps of the different versions along with some other useful data, as who did the edit, how many characters the given version have, an optional note which can be attached to the version, and a switch button in the Keep Forever column. From this screen you can preview a revision, restore it, compare it to another, keep it on, and delete it.
The intriguing new thing, the Keep On/Forever option allows you to store that version indefinitely. Using an example is an easy way to explain this feature. Remember the Maximum Versions setting? If you set that to 5, then 5 versions of that article are saved. On the 6th one, the 1st version gets deleted so that there are still 5 versions left total. What if you want to keep the first one or any other article? That's where the Keep On setting comes into play. If you enable it for that article version, it won't automatically get deleted from the list, but rather will remain there untouched. It's basically a "lock" feature that prevents deletion.
Content History in the Other Components
You can repeat the above process for the other components that have Content History built-in:
Best of all, there is an API wich makes easy for developers to add to their custom components easy integration with Content History. So hopefully there will be more and more components offering this neat tool.