Originally Posted by ******

MySQL is just a method of saving data at the backend, it is similar to using SQLite or just plain files. IMHO advertising it as a server feature is completely stupid - it doesn't make one blind scrap of difference to your players where your data is stored, only to you personally.

If you don't know what it is, don't worry about it - it is not something that will make your server better for your players, just one of a number of methods of providing persistent storage (i.e. player accounts etc). If you want user accounts just stick to what you know.