The Exchange Server 2010 Beta (download) offer the ability to view e-mail by conversations, but also the option of "muting" any thread that a user would rather not take part in. Among other features is something called "MailTips," which offers warnings when one might be about to commit an e-mail faux pas. For example, it will warn a user if they are about to send an e-mail to a large distribution list or if they are going to send an attachment outside their company's firewall. Many of the features work in the Web-based Outlook Web Access program, but to use them on the desktop will require Office 2010.

Source:→ CNet