The Wall Street Journal goes in-depth on a problem Google Maps has had for years: fake and deceptive business listings posted by scam artists that crowd out legitimate local businesses—as many as 11 million such listings at any given moment, according to experts.

Online advertising specialists identified by Google as deft fraud fighters estimated that Google Maps carries roughly 11 million falsely listed businesses on any given day, according to a Journal survey of these experts.

They say a majority of the listings for contractors, electricians, towing and car repair services, movers and lawyers, among other business categories, aren’t located at their pushpins on Google Maps. Shams among these service categories, called “duress verticals” inside Google, can snag people at their most vulnerable.

Those experts and Google disagree as to the extent of the problem. (Which is exacerbated by how easy it is to set up a business listing.) And the scam artists aren’t simply displacing local businesses: they’re resorting to outright extortion: pay up, or we’ll swamp you with bogus listings. [Engadget, The Verge]