PRODUCTS : REAL ESTATE AND SITE SIGNS Telling the public that property is available is essential for real estate and development businesses. However, these signs can be used to tell others that your business is helping to make a project grow. Smaller real estate signs are frequently used to help sell homes. These signs are increasingly being used by trades and construction businesses to advertise while working at a customer site. It is also a great way to tell the neighbors who is doing that professional work.