The court has a sua sponte duty to give CC 101, limiting jurors to considering evidence that is presented in the courtroom. (See People v. Carter (2010)182 Cal. App. 4th 522.)
It is critical that jurors be instructed that they cannot conduct any independent research on a case and should not discuss the case, even with other jurors, until it is completed. (People v. Danks (2004) 32 Cal. 4th 269, 298-300.) With the advent of new technology, such as text-messaging, twittering, etc., the court should emphasize that no means should be used to communicate with others regarding the case and that a violation of this rule is considered to be juror misconduct.
In 2010, CC 101 was revised to specify that, in addition to prohibiting jurors from sharing information by writing, by e-mail, and on the Internet, jurors should not use telephones, or “any other means of communications.” The CC Committee explained that it deliberately did not “choose to list specific means of inappropriately sharing information with electronic devices by name. The committee concluded that a list of specific Web sites such as Google, Facebook, and My Space is likely to require constant updates because popular Web sites come and go very quickly in the digital age. Moreover, when jurors hear a blanket admonition not to communicate with others about the trial, that admonition may be undercut by a list of specific forbidden means of communication. After listening to a long list, jurors may even conclude that modes of communication not mentioned are permitted.”(See Advisory Committee on Criminal Jury Instructions, Report to the Judicial Council for meeting of April 23, 2010, pp. 3-4.)