There's a thread on here but can't think where that gives instructions on how to PIN...but you pull up your PIN by going to Options and selecting Status. That will show your PIN. When you "PING" a contact, that means you're sending them an alert letting them know that you're trying to reach them.
Every BlackBerry device has a unique hardware identifier called the PIN. BB users can send direct PIN-to-PIN messages and chat with BlackBerry Messenger. This uses very small data messages and does not count as SMS text messaging.
PINGing a contact makes their BlackBerry vibrate, and I think also play their message alert tone, to get their attention.
You can also find your pin by typing "mypin" on any screen on BB. If someone has their phone on silent, a "ping" will still be heard. I personally do not use this feature unless I really need to contact someone.
Once you have established your pin, have fun and add contacts via their pin and then you make great friends and have nice chats on BB messenger.
As you can see, some post their pin numbers on CB and some do not. Before you know it, you will have loads of BB buddies, and will be truly addicted. You will never let the thing down.
A pin is a number specific to each bb and can be used to either pin msg or add someone to bbm. A PING!!! is like an alert to get someone's attention as another other user posted earlier. Dug up an old thread didn't we?