The ascii format is (usually) used for visual artwork made with text. The ASCII standard is as old as 1963, but text based art has been around since the late 19th century with the typewriter as a medium. Today, ascii is frequently used as a catch-all term for all text based artwork on computers.
BotB's ascii format has also been used for a variety of other text based battles, such as programming and creative writing.
_____________
|_.______.__||
| _||------|._||
| _||____|__||
|_. ______._||
|_||-------|_||
|_||-------|_||
|_||-------|_||
::::::::::::::::::::
____________
| __________||
| ||
| ||_________
|________ __||
------------|__||
________|__||
|__________||
::::::::::::::::::::
___________
| _______|_|
| ||
| ||
| ||
| ||
| ||__________
|__________|_|
:::::::::::::::::::::
_____________
|____ ____|_|
-------| ||
-------| ||
-------| ||
-------| ||
-____| ||_____
|__________|_|
::::::::::::::::::::::
_____________
|____ ____|_|
-------| ||
-------| ||
-------| ||
-------| ||
-____| ||_____
|__________|_|
::::::::::::::::::::::