Wagn lets you enable commenting on a card with a friendly comment box. User comments simply get added to the end of the card's content.
This is done via card permissions. Anyone with comment permissions on a card will see the comment box. Anyone with edit permissions on the card can edit all the content, including the comments, so that interesting comments can easily be reworked into the card's core content.
comments+description
This is done via card permissions. Anyone with comment permissions on a card will see the comment box. Anyone with edit permissions on the card can edit all the content, including the comments, so that interesting comments can easily be reworked into the card's core content.