graffiti - NicheInterests/mistfunk GitHub Wiki
Nominally, graffiti is simply the plural of graffito, something written somewhere. Historically, the term has been used in reference to vandalism, casual notes left in places -- like on walls -- where writing is not expected or desired, ranging from obscene Latin remarks in Roman ruins to "Kilroy was Here" during WWII. More recently, in the '70s and '80s it was elevated as one of the four pillars of hip-hop culture (along with MCing and turntablism, which have analogues in the underground computer art sphere, and breakdancing, which really has none.)
BBSes would often host "graffiti wall" doors (functionally the same as a "oneliner" door), which encouraged callers to write a brief bit of nonsense on their travels through the bulletin board outside the structured discourse of a message base, but the space only allowed textual messages (albeit tinted in [angry fruit salad] colours through the use of [pipe code]s) and not illustrations. A graffiti wall can be used as a wider metaphor for a joint canvas where numerous artists can throw down contributions literally alongside those of their colleagues, though in practice these are rather rare in the underground computer artscene.
As the underground computer art community emerged in tandem with the mainstreaming of hip-hop culture into the wider popular youth culture, graffiti street style typography (eg. incorporating pointing arrows into letters, or drawing crowns above them) specifically proved very influential in logo design among ASCII artists, ANSI artists and [high resolution] graphics designers.
Some underground computer artists don't just have interest in graffiti street style aesthetics but are in possession of direct experience in actually throwing murals up on walls with cans of Krylon... but it may be hard to get them to speak definitively on the topic as, like cybercrime, it is another similar realm where acknowledgement of involvement sometimes amounts to implicating oneself in a criminal activity, and the statute of limitations may not yet be up.
In one final overlap of the two subjects, over the long years some textmode art enthusiasts have been moved to consider the problem of reproducing computer art on walls, and some have indeed gone so far to undertake prototype reproductions, devising stencils on a grid or tracing over projections with paint. (Some are content to allow their wall ornamentation to be temporary and exist solely as projections.)