obt
Stands for 'Obvious Tastelessness' or 'Old but Tasteless' from the Alt. Tasteless group. Used like a P. S. but with more trash and less class.
I posted my rant about my ex and added a P. S. that was more tasteless than my ex's life.
He sent me a message and then added an OBT about his cat's bad breath.
She wrote a whole letter and tacked on an OBT that made me want to throw up.