Sony is rolling out version 3.21 firmware for the PS3 which will disable the "Other OS" feature built in the PS3 console as it creates "security" concerns.
It is not a mandatory upgrade but, keep in mind you will lose access to PSN and any future games that require the 3.21 firmware. Some speculate that the main reason for the firmware update is to prevent piracy.
Using Linux and similar platforms enables the user access to low level file systems and bypasses forms of copy protection.