Facebook is increasingly being used in courts to decide who is—and who isn't—suitable to serve on a jury, the latest way in which the social-networking site is altering the U.S. court system.

Prosecution and defense lawyers are scouring the site for personal details about members of the jury pool that could signal which side they might sympathize with during a trial. They consider what potential jurors watch on television, their interests and hobbies, and how religious they are.

Josh Marquis, district attorney of Clatsop County in Oregon, did background searches on Facebook to help pick a jury for a penalty trial last summer to determine if a convicted murderer should get the death penalty. He was looking for clues on how potential jurors might feel about the defendant, a man who killed a couple as a teenager in 1988. The jury imposed the death penalty.

Jury consultant Amber Yearwood in San Francisco found that one potential juror in a product-liability case last year held strident opinions on a host of issues, and dispensed unsolicited medical and sex advice. "Often juries offer opinionated people like that the perfect opportunity to wield their influence," said Ms. Yearwood. The prospective juror was bounced.

Some legal experts oppose this growing practice of scouring social-media sites, arguing that the traditional jury-selection process, which involves lawyers questioning prospective jurors, provides more valuable information than out-of-context online comments.

"I don't think we should abandon that system in favor of Internet snooping," said Jason Schultz, co-director of the Samuelson Law, Technology & Public Policy Clinic at the University of California, Berkeley, law school. "There are a number people who post who they want to be, as opposed to who they are."

Read the full article at the Wall Street Journal