Mention users

A good way to get someone's attention is to mention them in a comment or a task. They will get an email notification with the relevant information. Just start typing @ and the user name - you'll get a suggestions with autocomplete. Choose the person from the popup and you are done.

If you need to notify all the users in the project then just type @all .

Mention users

You can enable and disable this notification option under the profile page. It is enabled by default for all users. You won't get multiple notifications if you have multiple same type options enabled.