Laws in several states, including Florida, New York and Washington, require recorders to redact personal data from online records. But removing such information can be a huge challenge because of the sheer number of documents that need to be examined.

Foglesong said that in Orange County each image was reviewed once by redaction software from Mentis Technology Solutions LLC and then manually checked by workers. "We learned that software combined with a human review is much more dependable than human eyes searching page after page," she said.

Software-only approaches are also unreliable said Dana DeBeauvoir, clerk of Travis County in Texas. "It's definitely not the automated process that software vendors will have you believe," she said, adding that workers have to double-check documents to verify they need to be redacted and to ensure proper redactions have taken place. The wide range of document formats and the fact that some documents are handwritten can pose problems for redaction software applications, DeBeauvoir said.

Since public records laws prohibit recorders from altering originals in any form, it was also necessary to make copies of the images before making redactions, she said. This can impose an additional storage burden which, while small, still needs to be factored into costs, she said.

Travis County removed all document images from its Web site in June this year because of identity theft concerns and started putting them back online last week after redacting sensitive information. DeBeauvoir said about 11 million documents had been redacted and restored another five million newer records will go back online soon, she said. "I would give the quality of the work an A+," she said.