Securely configuring MySQL on MacOS X

This link provides a good tip for securing MySQL from unwanted attention and aiding performance in OS X.

As a summary, you just add the following lines to the my.cnf file :

[mysqld]
skip-thread-priority
skip-networking

skip-thread-priority is an optimisation under load conditions.
skip-netwroking prevents the default service coming up on port 3306, instead it only comes up on the file system socket - localhost.
You can also use the following in your config file instead of skip-networking :

bind-address = 127.0.0.1

This will let those clients that can't use the file system socket work and yet keep any network connections not originating on your machine from reaching your MySQL installation.

More intelligent configuration tips to align your installation to standards here.