When media mogul Rupert Murdoch's wife allegedly joined Twitter, it didn't take her long to earn a "verified account," one of the few status symbols available to known individuals on the social media network. Days later, the account was revealed to be a fake, leaving journalists the world over wondering how Twitter slipped up so badly.

In the ensuing media flurry, Twitter was revealed to have committed a minor clerical error: they "verified" the wrong Wendi Deng Murdoch. But that opened up a whole new case of questions, especially from journalists wondering how they can take the symbol seriously if there's a chance an impostor may slip through.

And now, it comes out: Twitter only verifies the accounts of people who pay $15,000 or more in advertising over a three month period, according to a report by Ad Age on Tuesday.

The only other way to get verified is to show Twitter that someone is trying to impersonate you, or be invited to Twitter's "Promoted Tweets" program. That's what Andy Cohn, publisher of music magazine The Fader, was told when he called a Twitter sales rep to request verification for his publication, Ad Age noted.

Twitter's "verified accounts" had previously only been reserved for top-tier celebrities, politicians and other famous individuals or organizations. They were launched after a rash of accounts impersonating well known people began fooling reporters.

Since Twitter took their verification application form offline due to a massive influx of requests, their criteria for verified accounts has been something of a mystery, with some famous individuals going unverified and others being verified immediately.

While Twitter is often lauded by the media for empowering users, giving them the ability to instantly share information the world over, it seems the social media service hasn't forgotten its wealthy constituency either.