Pinging is a test that shows a couple things, first off that your DNS (Domain Name Server) can resolve an IP address (address of the website you type in) and secondly it test how stable the connection is by returning the time it takes for the website to respond to the ping. Think of it like a sonar ping on a submarine, in fact that is where it gets it's name. With a successful ping you'll see something like this:
Microsoft Windows [Version 6.3.9600]
(c) 2013 Microsoft Corporation. All rights reserved.
C:\Windows\System32>ping www.tomshardware.com
Pinging a1768.w7.akamai.net [204.191.12.48] with 32 bytes of data:
Reply from 204.191.12.48: bytes=32 time=13ms TTL=60
Reply from 204.191.12.48: bytes=32 time=9ms TTL=60
Reply from 204.191.12.48: bytes=32 time=9ms TTL=60
Reply from 204.191.12.48: bytes=32 time=9ms TTL=60
Ping statistics for 204.191.12.48:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 9ms, Maximum = 13ms, Average = 10ms
C:\Windows\System32>