Social media has increasingly become an issue with regard to criminal conduct. There are several ways by which social media relates to the practice of law.
There are crimes that are committed through social media, like disseminating obscenity. Sometimes just forwarding a picture or posting it to an account can constitute a crime.
Prosecutors are using social posts as evidence in prosecuting all kinds of crimes. People are committing crimes and then posting information about the crime on a social media site.
Defendants are using social posts as defense. Often people who claim to be victims post conflicting information on their sites.
Lawyers use online personal data to determine whether they want to use a specific juror on a case. Jurors give clues about their views and prejudices that lawyers can use to predict their views in the courtroom.
Often people do not consider the consequences of their actions when they're posting this information and they are surprised when the information comes up in court. Just remember that facebook post could cost you some time in jail.