date/time created with oldest first
date/time created with newest first
most recently active first
Additionally, each folder and discussion contains a "sort sequence" field accessed by the Edit Folder or Edit Discussion button. Items assigned a sort sequence number are sorted in that order, with the highest number sorting to the top. Discussions with the same sort sequence number are further sorted according to the setting in the control panel.
V5.0+ If you EDIT the folder and select the "Sorting for..." option from the "Other Folder Settings" drop down menu, you can install custom sort sequences for items within the folder.