eXo Mail is an application part of eXo Collaboration Suite (eXo CS)
It includes many many features and today I will introduce one of my favorite: the different views available to read the mail list.
The first one is the thread view which displays the related message in a tree as shown in the next screenshot:
In fact there exist 3 default views: the normal list view, the threaded view and the conversation view
The conversation one is a bit like the gmail view