You might be able to, but it's neither guaranteed nor straightforward. I suggest you read this article first to understand how Thundebird mail tags work: http://kb.mozillazine.org/Tags You will see that the only way to get tags that have been set on one computer to show on another is via the mail server, and whether that is possible depends on the services offered by your mail provider. The article suggests a method of finding out. Anyway it would only work if you have an IMAP mail account. If you do, a more reliable way to work with your colleagues would be via mail folders. Suppose, for example, that you read the incoming mail and then move it into folders called 'for X' , 'needs response', 'waiting for more info' or whatever. If your colleagues' computers are subscribed to those folders they will see exactly what you have done, and you in turn will see what they have done when they have dealt with messages.