" Is it OK to pop up a notification bubble if you only do it every once in a while?"
No it isn't. For critical or really important messages that require user decisions, yes.
The idea of using pop-ups for notification of important or critical issues is not the problem though, he problem is so many teams within Microsoft and software vendors abused it. For example - "There are unused icons on your desktop."
Worse than that is the abuse by installing an icon in the notification area - have you seen the appalling state of many Windows users' notification area? 20 to 30 icons is not unheard of.
No it isn't. For critical or really important messages that require user decisions, yes.
The idea of using pop-ups for notification of important or critical issues is not the problem though, he problem is so many teams within Microsoft and software vendors abused it. For example - "There are unused icons on your desktop."
Worse than that is the abuse by installing an icon in the notification area - have you seen the appalling state of many Windows users' notification area? 20 to 30 icons is not unheard of.