The next version of Microsoft's corporate email server will allow emails to be listed as 'conversations' and make it possible to 'mute' any thread you don't want to read.
The function is similar to one already seen in Google's Gmail, and will appear in Exchange 2010.
The software goes into its public beta today, with a final launch in the second half of this year.
Also included are 'MailTips' which offers warnings when one might be about to commit an e-mail faux pas such as sending giant files to a large distribution list.