Notification behavior depends on a number of settings including:
- The type of user account that created the case
- Whether or not a person's account has notifications enabled
- Who the case is currently assigned to
- Whether or not a person has "subscribed" to a case
- Whether or not a person is using the AutoSubscribe plugin
- Whether or not you're using the Notify plugin to notify additional people.
Anonymous and Community User accounts won't receive any automatic notifications after filing a case.
For a Normal or Administrator user to receive notifications, they must first ensure they have enabled notifications: My Settings -> Options -> Email Notifications (this setting defaults to On).
Let's say we have Bob and Jane who are both Normal users in FogBugz. If Bob creates a case and Assigns it to Jane, provided they both have notifications enabled, only Jane will receive a notification ("A new case was assigned to you in FogBugz..."). If anyone other than Jane then modifies that case (change the category/priority, make a comment, etc.), Jane will receive a notification about what changed so long as that case is still assigned to her.
In order for anyone (other than the person the case is currently assigned to) to receive a notification they can "Subscribe" to the case (i.e., go to a case, and click on "Subscribe" at the bottom of the left-hand column). Once subscribed to a case, that person will receive notifications for any changes made to that case, except for changes that person makes themselves.
The AutoSubscribe plugin can automate the "Subscribe to this case" behavior such that you are automatically subscribed to any case you edit (for example).
Finally, if you'd like to explicitly notify someone there is also a Notify plugin which allows you to explicitly call out additional people you would like to notify about the changes you're making.