The notification area is a good idea in general, but many plugin authors have figured out they can use this to push marketing messages to users. Some even present notifications that take up a lot of room. If you get more than one at a time, the notifications can cause alarm or confusion for clients and interfere with the admin experience. To hide WordPress notifications, simply enable this module to either show them only to certain roles, or move them to a specific location where they won’t interfere with the admin area.