Agostino Iacurci, a young street artist, said he went through a "tag" phase but now does "murals" -- often as part of the renovation of working class neighborhoods. "Before I couldn't care less about what people thought but now I like expressing myself and getting a reaction as a person and an artist. The street offers this type of judgement every time pedestrians walk by," he said.
A work of street art entitled "superpope" captured the imagination of Romans earlier this year -- a picture of popular Pope Francis in his white cassock as superman.
The artist, MauPal, said he sees street art as social. "Urban art does not talk about itself or about the artist but about people, what surrounds it, what's in the news and what is aesthetic," he said.
That view is shared by the "Poeti der Trullo" -- a collective of young poets based in a poor suburb of the city who write their verses on the walls. "Our aim is to respect Rome by giving it something more, without disfiguring it. Maybe we can get a smile or a tear from a passer-by," they said in a statement.
Rome's waste collection agency AMA said it is forced to clean up the mess -- with hundreds of interventions on a total of 700,000 square metres of walls, or twice the surface area of the Vatican.
"If you include the number of people and vehicles deployed and the cleaning products used to wash off the graffiti, the annual cost for cleaning is between 1.2 and 1.5 million euros," said Anselmo Ricci, head of the municipal police corps in charge of preserving Rome's historic centre.
It is a heavy cost for a city administration that in February announced a budget deficit of 816 million euros.
"It's not enough," said Massimiliano Tonelli, founder of the website Romafaschifo.com (Romeisdisgusting.com). "The dirtier the walls, the more people are inclined to dirty them. It's the scratched car theory," he said.
Ricci is critical too but his reaction is more tempered. "It is a serious violation but it's true that sometimes I see graffiti that make me smile. They show up the jolly character of Romans."