This article recommends the UNIX nobody user to access MySQL from Joomla scripts. Is this standard practice? Moreover, is it reasonable to use it, say, both for Joomla and WordPress?
Questions on Server Fault are expected to relate to professional server, networking, or related infrastructure administration within the scope defined in the FAQ. Consider editing the question or leaving comments for improvement if you believe the question can be reworded to fit within the scope. Read more about closed questions here.
This question makes no sense. You don't use unix users to access mysql, it has its own access control and its own users/passwords.
The second part of the question makes some sense and the answer is no. As with anything, separate privileges as much as possible. Create separate users for joomla and wordpress and don't give them access to each others schemas.
No, this article does not recommends the UNIX nobody user to access MySQL :
Here are a few security tips :