Thinking back, it does seem like tagging shows up more on infrastructure than adspace but I think that might just be because there is a lot more money invested by advertisers in replacing ads than there ever is on cleaning/repainting public structures. The signs at sporting events and billboards change hands or are updated fairly regularly by the nature of the advertising company moving to a new client whenever a contract ends, but walls and public signage are often only replaced or repainted once every few years at best.