Ostergren said efforts to stop Virginia's Hanover County, where she lives, from posting images of public records online have succeeded so far. But 14 of the state's 121 cities and counties do make records available online, she said, adding that the same thing is being done by counties in states such as Pennsylvania, North and South Carolina, Ohio, Georgia, Arizona, Texas and New York. That includes all five boroughs in New York City, according to Ostergren.

Fogelsong noted that Orange County residents who want information removed from documents can request that it be redacted. "I would love if people would check their records on their own" to ensure that no private data is publicly disclosed, she said.

But Ostergren dismissed such advice, saying Florida and North Carolina are currently the only states that allow residents to ask for their Social Security numbers to be removed from online records that were already posted.

On the other hand, many states have given county clerks the power to refuse to record new documents containing personally identifiable data, Ostergren said. Overall, though, "this online records mess has been the best-kept secret," she added. "Ninety-nine percent of citizens haven't a clue that the records are online in the first place."

Computerworld's Ken Mingis contributed to this story.