In a criminal trial the prosecution tries to reconstruct the past as it existed at a particular moment in time in order to prove that the accused committed the alleged act beyond a reasonable doubt.
The rise of social media has provided the prosecution with the means to paint a much clearer picture of the past. Many individuals openly share information in the digital realm about their thoughts, their preferences, their associations and their activities. The electronic record of this information provides the state with the potential for unprecedented access into the minds of its citizens in the context of a criminal investigation.
While the prosecution has benefited from the popularity of social media, enhanced clarity with respect to what happened in the past cuts both ways.
Consider a Crown witness who is an unreliable narrator. The electronic record of comments that a witness previously made on social media may be a rich source of material for cross-examination by Defence counsel should the witness try to mislead the Judge.