I've noticed that many articles don't get carried forward to the documentation for the latest version of Alfresco. The latest version of Alfresco is what is linked from the front page.
I understand that things have to be removed sometimes since it gets obsolete/out of date.
One example is this page Activities feed email notifications list | Alfresco Documentation only available for 4.1
That is useable information that is valid for later versions as well.
I could carry on with more examples, but this one example should be enough.
I usually think complaints about Alfresco documentation isn't fair, and there is lots of information available in docs.alfresco.com. It is just how it is structured, and that one piece of information is there to be suddenly gone for another version. This means that the search functionality must have all versions of Alfresco must be in the search, if you limit to the version you are actually using, there is a high risk of you missing available information. But if you do search with all versions enabled, the number of hits gets too large, and you won't find it anyway.