Netcat is well known as a swiss army knife tool. Its a small exe works in windows as well as in all flavor of Linux. Netcat is normally used in a hacking as a backdoor becuse of its small size and you will find in Metaexpoits framework using netcat using as a backdoor.

Netacat wont work if the pc has anti-virus(AV) installed on it. Normally all AV detect netcat as a backdoor and delete it.

Hobbit (hobbit@avian.org) created netcat in 1995 as a feature-rich network debugging
and exploration tool. Its purpose was to be able to create just about any type of network
connection. According to Hobbit2-
Some of the features of netcat are:
· Outbound or inbound connections, TCP or UDP, to or from any ports
· Full DNS forward/reverse checking, with appropriate warnings
· Ability to use any local source port
· Ability to use any locally-configured network source address
· Built-in port-scanning capabilities, with randomizer
· Built-in loose source-routing capability
· Can read command line arguments from standard input
· Slow-send mode, one line every N seconds
· Optional ability to let another program service inbound connections

Some of the potential uses of netcat:
· Script backends
· Scanning ports and inventorying services
· Backup handlers
· File transfers
· Server testing and simulation
· Firewall testing
· Proxy gatewaying
· Network performance testing
· Address spoofing tests