Postgres to Mysql

I've administrated a few Postgres database servers in the past, but have just started working with mysql, as I've volunteered to admin the mysql server run by my school's comp sci student organization. I'm going through the mysql manual on the mysql website right now, starting to figure out the differences and similarities between the systems. It seems like security and user administration is handled a bit differently between the two, but how exactly isn't clear to me yet.

Having fooled around with it a bit more, I've found that it looks like there is one server running, and that it has a number of databases running on it. It looks like there is one main listing of users, which is kept in the mysql database. From what I understand, each user is linked to a particular host, or network location where they login from. I've installed everything on my debian stable system, and it looks like it's added a few extra users. I was expecting just the root user, but when running the following command, I got:

mysql> select host, user from user;
+-----------+------------------+
| host | user |
+-----------+------------------+
| cthulhu | |
| cthulhu | root |
| localhost | |
| localhost | debian-sys-maint |
| localhost | root |
+-----------+------------------+
5 rows in set (0.00 sec)

I assume I should remove a few of these?



Anyway, I was just wondering if anyone had any advice for one moving from Postgres to Mysql administration.

Cheers!