Mozilla Thunderbird 3.3 (Miramar) is shaping up to be a pretty significant upgrade to the open-source email app. One thing I always find myself wishing for, however, is conversation view. I've been using Gmail for years now, and conversations have become part of the way I work.A new add-on from Mozilla Labs brings a richer threaded view to Miramar. Once installed, clicking a collapsed thread in your inbox causes the entire conversation to load in Thunderbird's reading pane. Unread messages are expanded and those you've previously read are collapsed -- just like Gmail. Buttons are also added to reading pane which allow you to expand or collapse all messages or pop the conversation out into a new tab.Read more: DownloadSquad