That's what I'd said in a mailing list and someone asked me what that meant.
"Feel free to ping me" is generally used by computer folks to mean "don't hesitate to get in touch with me about this".
"Ping" is actually one computer mechanism to determine whether another machine is indeed available on the network. You send a "ping" to a computer and receive a response from it. Thereby you know that its operational. I've over simplified it, but that's the essence :)
What do you think ?