With the notification manager users and groups can control what things they want to be notified of and how.
The first OpenPsa component to implement notifications is OpenPsa Calendar, allowing users to choose whether they get emailed about new events or not:
For now the notification manager supports only emailing or disabling notices, but other transports are being planned. For some things SMS, Jabber or even Growl could make more sense. For example, it would be nice to get a Growl notice when a client approves a completed project.