Blatantly Ignorant Ass Hole. Typically refers to people who overuse the internet shorthand typing style and also use extremely poor grammer. Not to be confused with 1337 talk.
An example of what a BIAH would say: OMG Liek did u c wat julie was wearing 2day? She didnt even check 2 c if it matched wit her shoes. i tryd 2 talk 2 her but she was all liek "OMG i will change it b4 the dance."