What's the difference between the Oracle SYS and SYSTEM accounts?

Question

What are the differences between the Oracle SYS and SYSTEM built in accounts?

Edit: Apart from 3 letters!

Answer 1

SYS can connect AS SYSDBA, SYSTEM cannot.

SYSDBA privilege is required to perform certain administrative tasks, like CREATE DATABASEand DROP DATABASE, and query any tables despite GRANT'ed permissions on them.

In fact, whenever you connect as SYSDBA, you become a SYS.