wiki graffiti

wiki graffiti is a more neutral name for what is often called wiki vandalism or (worst) just vandalism as if it was as bad as smashing something. In real life, graffiti is sometimes entertaining and relatively easily undone and sometimes rises to art.

Replacing the useful function of pages might be called vandalism though it too is very easily undone.

Only sysop vandalism is usually worthy of the name since only a sysop has the power to make changes that regular editors can't easily undo.