As an outreach tool, graffiti can be used to support (or oppose) a sports team, a school, a political idea or a specific candidate. Or it can be a highly personal combination of all these at once; an uncompromising glob of expressive visual goo.
In the political arena, particularly during an election cycle, graffiti is a deliberate weapon often kept locked and loaded—there’s no telling how much is sanctioned by campaign managers and how much comes from passionate supporters or opponents.
In the promotional arena, film and music distributors have mastered the art of legal and illegal “plastering” of posters all over construction areas and downtown locations prior to release day. This is considered to provide “good value” even when fines are levied and legal fees added.
Other high-profile businesses also use similar marketing efforts, and their message can also be seen (legally) on buses and other modes of public transportation.
Since I would not refer to a careful rendering of a business name or logo as graffiti, I would not use the term to describe anything openly funded with corporate or public money.