When you have a database of books or movies, some of the titles begin with "The." If you do a regular ORDER BY on the table, all the titles that start with "the" get clumped together. One option is running an unsorted query and sorting in PHP, but it would be better to sort at the database level. Here is a query I came up with to do that, using an IF function in MySQL!
I recently discovered an excellent tutorial on setting up Postfix and Courier to use virtual users read from a MySQL database. This caught my attention because it is a much better setup than having real system users for all email addresses, as it allows much more flexibility. I finally set aside some time to set up a real mail server.