Why are sockets important in computer communication?

Question

please do not define sockets

Answer 1

In client server computing sockets are essentialfor communication between specific applications of specific computers. For example if MSN messenger on Computer A would like to send messages to other computers then sockets are used for communication between applications on same or different computers

Answer 2

Same reason doors are important in buildings, except that packets can't come in through windows or holes in the wall..