You can forward a text copy of an item to anyone you like. If you click a user's name in the left hand menu, then that user's email address appears in the text entry box on the right.

You can also enter arbitrary email addresses in the text box at the right. Simply separate each email address with one or more spaces. Make sure to use complete email addresses, such as joe_user@somewhere.com, since Willow is not Outlook.

You can also forward items by clicking the checkboxes at the bottom right. Click "myself" to send yourself a copy. For tasks, click "assignee" to send a copy to the current owner of the task, and click "creator" to send a copy to the task creator.

All such email communication is logged in the item's followup comments.