Explain these Netstat outputs?

Can anyone explain the meanings of the following types of Netstat -a -n -o outputs?

Proto Local Address Foreign Address State PID

TCP [ : : ]:PortNumber [ : : ]:0 LISTENING Usually a Windows Process

and

TCP 0.0.0.0:PortNumber * : * State field is empty Background Process or Web Browser Application


I'm checking the computer for external monitoring attempts and interested in determining how much of the contents of the HDD and network usage (web browsing and networked windows processes) can be monitored by third-parties.