When Google’s Gmail launched in 2004, one of its more notable features was its use of conversational sorting. That is, Gmail grouped emails–including your own responses–into conversational threads. With one click, you could view an entire exchange of e-mails that spanned days or weeks.
Though few realize it, a similar feature has been available in Microsoft Outlook for years. The conversation view in Outlook 2003 and 2007 is accessed under: View > Arrange By > Conversation. In Outlook 2010, select the View tab and click the check box next to “Show as Conversations.” Your emails will automatically sort themselves into groups.
One note: in versions prior to Outlook 2010, the conversation view only includes emails you’ve received, not sent. For an experience truly similar to Gmail, you’ll need to create a search folder that includes all of your email (sent and received) and apply the conversation view to the search folder.