BALTIMORE — THE reputation business is exploding. Having eroded privacy for decades, shady, poorly regulated data miners, brokers and resellers have now taken creepy classification to a whole new level. They have created lists of victims of sexual assault, and lists of people with sexually transmitted diseases. Lists of people who have Alzheimer’s, dementia and AIDS. Lists of the impotent and the depressed.

There are lists of “impulse buyers.” Lists of suckers: gullible consumers who have shown that they are susceptible to “vulnerability-based marketing.” And lists of those deemed commercially undesirable because they live in or near trailer parks or nursing homes. Not to mention lists of people who have been accused of wrongdoing, even if they were not charged or convicted.

Typically sold at a few cents per name, the lists don’t have to be particularly reliable to attract eager buyers — mostly marketers, but also, increasingly, financial institutions vetting customers to guard against fraud, and employers screening potential hires.

There are three problems with these lists. First, they are often inaccurate. For example, as The Washington Post reported, an Arkansas woman found her credit history and job prospects wrecked after she was mistakenly listed as a methamphetamine dealer. It took her years to clear her name and find a job.