OMG! What is that on my car's license plate?

That's the question asked by 10,000 drivers who registered their vehicles in North Carolina last year and got registrations starting with "WTF."

Long just an innocuous combination of three letters, like OMG ("Oh my God!") WTF is now heavy with vulgar connotations: it is an oft-used email and mobile phone abbreviation that means "What the f***."

In North Carolina, WTF plates were issued to some 9,999 drivers last year, including elementary school teacher Mary Ann Hardee, who teaches computing and technology, the News and Observer newspaper reported earlier this month.

"She wasn't hip to the Internet-age significance of her new license plate -- until she caught her teenage grandchildren giggling at it," Dan Kane, staff writer at the paper wrote.

Hardee, 60, told the paper she "developed this real self-consciousness" once she found out what her number plate meant in techno-shorthand.

She petitioned the Department of Motor Vehicles, which ordered that she and everyone else who had a WTF number plate should receive new plates FOC -- free of charge.

This year, North Carolina registrations have three-letter combinations starting with the letter Y.

The Department of Motor Vehicles has carefully scrutinized the plates and deemed that none are offensive, according to the News and Observer.

They must have overlooked YBF, which means "You've been f***ed."