"USENET News" has been around since the beginning of the Internet and the protocol, while being tweaked just a bit here and there, has remained largely unchanged. USENET has a somewhat spotty past, having been the first target of pervasive, and often extremely tasteless, unsolicited commercial junk postings (SPAM) long before SPAM hit the eMail world.
Many long-standing problems surrounding abuses of news servers and content have caused many ISPs to preemptively block incoming traffic to end-users' port 119, thus prohibiting the operation of NNTP news servers by ISP customers.
If you find that your port 119 shows "stealth" (green/blocked) when you have deliberately lowered your security in order to detect ports being preemptively blocked by ISPs, it's almost certain that your provider is blocking port 119 to keep their customers from operating NNTP news servers.
The final IDENT RFC 1413:

http://www.ietf.org/rfc/rfc977.txt

http://www.faqs.org/rfcs/rfc977.html
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