Apple has been left red-faced after a billboard promoting hacked iTunes tracks was posted outside one of its flagship stores.
The billboard was promoting DoubleTwist, a software company run by famed hacker Jon Lech Johansen – otherwise known as "DVD Jon".
DoubleTwist removes Apple's copy-protection on tracks sold in its iTunes Music Store, which allows the files to be read by non-Apple devices.
The billboard was posted on the side of a subway exit next to Apple's major San Francisco store. It was intended to coincide with Apple's Worldwide Developer's Conference (WWDC) which took place last week.
But Bay Area Rapid Transport (BART), which owns the billboard space, removed the ad because the black background was "too dark", Mr Johansen claimed on his blog.
"How convenient for Apple that our ad won't be back up in time for Monday's keynote," Mr Johansen said on Twitter.
DoubleTwist changed the ad's colour to white, which was rejected, and then finally posted the billboard with a transparent background, after the WWDC had finished.
"Apple is a major BART advertiser (in the past they’ve plastered entire BART stations with iPod ads)," Mr Johansen wrote on his blog.
"Apple’s WWDC conference ends on Friday. It’s pretty obvious what’s going on here… I’m sure our ad will conveniently be back up after WWDC ends."
The Norwegian whiz-kid first gained notoriety when he cracked the DVD region coding system at age 16. This ultimately allowed consumers to buy and watch DVDs from anywhere in the world, rather than in specific regions decided by manufacturers.
Now 25, Mr Johansen has had several run-ins with Apple over efforts to help consumers "liberate" music from iTunes' copy protection regime with his doubleTwist software.
DoubleTwist received an undisclosed amount of funding from Norway's NorthZone Ventures and Geneva-based Index Ventures, which was an early backer of Skype, Last.fm and MySQL before their eventual sale to larger companies.