But once he is done, Mr. Birnbaum’s record will be clean. Which means that by the time he graduates from the University of Texas at Austin, he can start his working life without taint.

At least in the eyes of the law. In the eyes of anyone who searches for Mr. Birnbaum online, the taint could last a very long time. That’s because the mug shot from his arrest is posted on a handful of for-profit Web sites, with names like Mugshots, BustedMugshots and JustMugshots. These companies routinely show up high in Google searches; a week ago, the top four results for “Maxwell Birnbaum” were mug-shot sites.

The ostensible point of these sites is to give the public a quick way to glean the unsavory history of a neighbor, a potential date or anyone else. That sounds civic-minded, until you consider one way most of these sites make money: by charging a fee to remove the image. That fee can be anywhere from $30 to $400, or even higher. Pay up, in other words, and the picture is deleted, at least from the site that was paid.