Modules and organisations both allow anyone enrolled to use the ‘messages’ feature to communicate with other users enrolled in that same module/organisation. If you click on the Send an email copy to recipients, you can ensure that everyone will get a copy of the message as an email, regardless of their notification settings in My Dundee.
Although this can be a really useful way to communicate to your peers and other students in any groups you may be in, please be conscious of who might be receiving these messages. This tool is best used with small groups in modules, and should not be used to send messages to everyone in large organisations.
If you have any questions about how best to contact any users, you can contact your instructor (for modules), the leaders of the organisation, or Help4U for technical questions.