Shoutbox

So they're going to pin up their views to the previous note?

Well you could design a big table with on Word and design some posting notes that fit nicely within the table cells using Word or Publisher. And  so the table would be up on the board and you could have a box of the posting slips and a box of pins and so if you want to start or reply to a discussion simply write it down on the slip and pin it up in the next row in the table.