An anonymous reader writes with an excerpt from Wired about the one big problem that comes with crowdsourced data: enough eyeballs may make all bugs shallow, but may not fare as well against malice and greed: Maps are dotted with thousands of spam business listings for nonexistent locksmiths and plumbers. Legitimate businesses sometimes see their listings hijacked by competitors or cloned into a duplicate with a different phone number or website. In January, someone bulk-modified the Google Maps presence of thousands of hotels around the country, changing the website URLs to a commercial third-party booking site ... Small businesses are the usual targets. ....These attacks happen because Google Maps is, at its heart, a massive crowdsourcing project, a shared conception of the world that skilled practitioners can bend and reshape in small ways using tools like Google's Mapmaker or Google Places for Business. ... In February, an SEO consultant-turned-whistleblower named Bryan Seely demonstrated the risk dramatically when he set up doppelganger Google Maps listings for the offices of the FBI and Secret Service..