Here's one more that I stumbled over:
Five reasons why you should never use PostgreSQL -- ever
As the title suggests, it's mainly about PostgreSQL. However, a lot of it applies to MySQL, as well.
This is all about db4free.net and the database systems that it offers. The main focus are practical examples of the new features of MySQL 5 and 6 that should show you how to use them for your advantage in your daily life ;-).