Mickey Mouse has a tremendous recognition rate. Indeed, the cartoon mouse is the world's most famous personality - he's even better known than Santa Claus in the US!
But did a mistake by Disney in the 1920s cause it to lose its copyright over Mickey Mouse? Here's an interesting article at the Los Angeles Times by Joseph Menn:
Film credits from the 1920s revealed imprecision in copyright claims that some experts say could invalidate Disney's long-held copyright, though a Disney lawyer dismissed that idea as "frivolous." [...]
Copyright questions apply to an older incarnation, a rendition of Mickey still recognizable but slightly different. Original Mickey, the star of the first synchronized sound cartoon, "Steamboat Willie," and other early classics, had longer arms, smaller ears and a more pointy nose.
The notion that any Mickey Mouse might be free of copyright restrictions is about as welcome in the Magic Kingdom as a hag with a poisoned apple. Yet elsewhere, especially in academia, the idea has attracted surprising support.
"That 'Steamboat Willie' is in the public domain is easy. That's a foregone conclusion," said copyright scholar Peter Jaszi of American University's Washington College of Law after studying the issue at The Times' request.
The issue has been chewed over by law students as class projects and debated by professors. It produced one little-noticed law review article: a 23-page essay in a 2003 University of Virginia legal journal that argued "there are no grounds in copyright law for protecting" the Mickey of those early films.