A poorly made message board system coded in PHP. Known for being notoriously filled with security holes and inefficient coding.
XMB is so bad it makes ezBoard look like a million dollars.
by moi August 24, 2003
'Cross Media Bar' a form of interface, that goes across your screen, usually animated.
Sony VAIO laptops sometimes have XMB's.
by q1w2e3r4 July 21, 2008