We could even never have been using this tool but no one probably can say they never heard about it being called the TCP/IP Swiss army knife and that for its versatility. You can literally have hours of fun just exploring all the possibilities it enables. That said, netcat is a utility, which reads and writes over the network using either TCP or UDP protocol; and what makes it really handy is its ability to keep up the connection until the remote side of the connection is shut down. This makes it different from most of the applications, which just stop working after the last bit of data has been delivered. netcat is different; it keeps both ends of the communication channel in touch even if there is nothing passing through, so you can use it for repeated dispatches.
The Netcat can be used either in a server or client mode and from inside scripts too by adding network facilities...