When sent with a DWORD value of anything over 3, it will deliver you to your product-country-specific channel with the MOTD and last login info.
To clarify: Sending it while you're already in a channel, not right after logon.
[MyndFyre edit: congratulations, it IS possible to press the "Modify" link.]
Makes sense.. As 0x0A and 0x0B can be sent at any time as well, IIRC.. Nice observation though.