Naturally I want to have a transactional DBMS, so I always pick InnoDB as the MySQL storage engine. I also want UTF-8 support because the content I store is entered by users from all over the world. Hence not all of the tips and tricks shown here might be relevant for you, in fact, if you are happy with your system in production, do not change anything. Also note that many of these customizations are only relevant if you let Hibernate generate your MySQL DDL and schema for you.
This service lets you validate XML documents such as XHTML against the appropriate schemas. It performs a more accurate validation than the W3C validator.