Aren't the Messenger toasts also displayed in the bottem left corner? What about balloon tips for system tray icons? Also, other programs use this same position to show toast like boxes as it is actually the standard position given by Windows as it is the closest to the systemtray.
So, Plus! uses that same position too....
Of course, this can be programmed so the position can be choosen. And maybe this isn't such a bad suggestions afterall. Just pointing out why the toast displays where it displays and that isn't a random choice.