1) Committing suicide over something really stupid.
2) Failing to commit suicide over something really stupid.
3) Doing something stupid, which results in accidentally killing yourself.
4) Also sometimes used on the work safe boards for someone who deliberately posts porn, which is considered both "suicidal" (due to the ban that usually follows), but truly heroic.
Term originates from a grammatically incorrect poem posted at a myspace memorial for a boy (Mitchell) who killed himself when he couldn't find his ipod.
Yasmin Browder hung herself when her mother didn't let her watch big brother; she is an hero.