As someone who recently served on a jury and who also is a regular user of social media, I read with great interest a report in the May 7, 2012 edition of Massachusetts Lawyers Weekly on the decision of the Massachusetts Appeals Court in the case of Commonwealth v Werner (full opinion here). After the defendant had been convicted of larceny over $250, defense counsel discovered that one of the trial jurors had posted something about the trial on Facebook during the trial. This prompted a motion for a new trial which was denied which denial was the basis for the appeal.
The Appeals Court upheld the trial judge's denial of the motion for a new trial mostly on the grounds that there was no evidence that the Facebook postings put any extraneous information before the jury. The Appeals Court went on, however, to urge trial judges in their instructions to juries to be much more explicit in directing jurors to refrain from any digital discussion or comment about their jury service at least until such service was completed. "More explicit instructions about the use of social media and the Internet may therefore be required . . . Jurors must separate and insulate their jury service from their digital lives."
From my prior career as an attorney who handled a lot of criminal matters, I'm very familiar with the problem underlying this case. While a trial is a search for the truth, it is a search for the truth within the very strict confines of the adversarial system and the rules of evidence. Not every piece of information should be available to jurors. Jurors must base their verdict only on those facts that have been subject to cross examination by the opposing party and that are also allowed by the rules of evidence. If the jury is exposed to any information that reaches it without first going through this process, a mistrial must be declared. In the past, scenarios that resulted in new trials involved jurors conducting experiments on their own outside of court or third parties either purposefully or inadvertently passing information to jurors. Now that everyone with a smart phone or an iPad has access to "all the world's information" at their fingertips, the chances of extraneous information reaching jurors is greatly magnified.