Seven segment displays nowadays are commonly used in place of dot matrix display. They have found their use in places like microwave or fancy toaster oven or  the same on washing machine but before using them in all these places you need to interface the 7 segment display with    microcontroller or some more hardware will be required. But with the basic knowledge of 7 segments display you can use it   in front of your shop or you can display your name on it. 7 segment displays numbers from 0 to 9 and some alphabets.7   segment display are labelled a to g and decimal point is usually known as DP. DP is the common point. In common cathode display they are connected to ground and rest pin are connected to supply. Similarly in common anode DP are connected to supply and rest are connected to ground. You can also use more than one display according to your requirement.