Twitter appears to be in hot water with its hometown. The source of the friction has shown up all over downtown San Francisco in the form of tweets stenciled on streets as part of a guerilla advertising campaign.
"Twitter is like running up the down escalator," says one near a BART escalator. "Twitter is garbage and I am a raccoon," says another, stenciled near a garbage can.
They became popular fodder on, well, Twitter, with some commenters calling them "awesome" and "genius," while some questioned their legality.
And that's the rub. Regardless of whether you agree with the stenciled tweets' messages, which are created using a spray-paint-like chalk, they run afoul with the law, said Rachel Gordon, a spokeswoman for San Francisco Public Works Department.
"These ads are not sanctioned," she said. "Our sidewalks are not to be used for billboards."
She also warned that the company could be on the hook for the cost of cleaning them up.
"Our street cleaning and street inspection teams have been made aware of these illegal advertisements, and if it becomes necessary for us to remove them we will be sending a bill to the offender."
This isn't the first time San Francisco has taken a tech company to task for spray painting ads on city sidewalks. In 2012,and almost $20,000 in cleanup costs after the company's Peace, Love & Linux campaign. The city counted more than 300 instances on its streets of the simple stencil, which featured a peace symbol, a heart and a penguin -- the official Linux mascot.
Twitter's campaign comes amid an environment in which tech giants have become a symbol for wealth disparity and gentrification in the Bay Area. Many in San Francisco criticized a controversial "Twitter tax break" the city in 2011 that eliminated taxes involving payroll and stock options for six tech companies.
Twitter didn't immediately respond to a request for comment.