Sometimes, you might want to comment or interact with a challenge without necessarily dropping a specific idea to the challenge. To do this, just click the ‘Comments’ icon on the challenge card. Here, you can comment @mention other people and share links, in just the same way as you would on an idea. Comments and @mentions create notifications to relevant users, in the same way as they do for ideas.
On the comment thread, you can also see the change log detailing if and when the challenge has been edited.