I found this use of google spreadsheets to be pretty amazing, especially with how it interfaces with classroom so well.
The advantage to using a spreadsheet for discussions is… it is a spreadsheet!! Google Sheets are in your Google Drive, easy to locate. It can be embeded into another website or linked to from just about anything. Information in the spreadsheet can be sorted and organized. Formulas can be applied, Add-On’s can be used, charts can be generated. Since the discussion board is not in another platform, it is easy to save the discussion board.