I wrote an article in The Business Lawyer entitled "Ethical Email for In-House Counsel: What the Ethics Committee of the North Carolina State Bar Thinks of Your Use of the "CC" Field and "Reply All" Button" that was published today analyzing the North Carolina State Bar's position on these issues. The audience was in-house counsel, but most of it applies to all lawyers.
Here is an excerpt:
The next time you position your cursor over the "CC" field or the "Reply All" button on your email software, consider whether clicking your mouse could be a violation of the Rules of Professional Responsibility.
Today, contract negotiation is done primarily by email, and much of the early stages of claims negotiation is handled by email as well. When corresponding with an attorney representing the other side, a lawyer may not realize that merely copying the other lawyer's client can amount to a breach of his or her professional responsibility that could result in disciplinary action by the State Bar. On January 24, 2013, the Ethics Committee of the North Carolina State Bar voted to publish a proposed ethics opinion addressing a lawyer's professional obligations when corresponding with a represented party by email.