Lots of ways! However you must have an account on The Duck to do so.

Comments! Site members can leave comments in many places: on each other's profiles, comic pages, on tutorials, newsposts, and any place you see a "comments" box. If the "say it!" button is greyed out, it's because you need to log in before you can leave a comment.

Forums! The Duck's community forums are a great place to network and communicate with other comic creators and fans. There are forums for most general topics and they tend to be a friendly and welcoming place. You can access the forums via the "forums" link in the main menu bar at the top of most Duck pages:

Private Quacks (PQs)! This is a private messaging system internal to The Duck. Members can send and receive messages between each other. You can access the PQ system via your account tab: