I think that this is very anti-social. I think that the following excerpts from things I've written explain my view on this matter. Also note an item in the "How to find the right place to post FAQ", which says that you should not post to "a newsgroup which you do not read":
If you do not read a newsgroup, you cannot know what the subject of the newsgroup is, what the standards of behaviour are, what the frequently discussed topics are. Usenet does not exist to give you a free research tool. It is also considered incredibly rude to post a question to a newsgroup you do not read, and ask for replies in e-mail - by doing so, you are telling the people you want to answer your question that their issues are not important to you.
Much of this web page does not apply to the case where someone's request is not that the conversation continue off-line, but rather, they ask that it continue in both media. These requests usually take the form of a request "please cc me on your reply". Note, though, that much of this web page still does apply in that case, such as the quoted paragraph above about not posting to a newsgroup which you do not read. Thus I'm not willing to do the cc thing either.
Here first is a letter I wrote to someone following up a comment about this in a newsgroup, and following that are two responses to various people's taglines. (In fact, this letter was a continuation by e-mail of my second newsgroup response farther down, but the letter says it best, I think, which is why I put it first here.)
From: flaps (Alan J Rosenthal)
To: [deleted]
Subject: Re: Hacked system: Possible warning and advice requested
Date: Wed, 14 Oct 1998 09:28:02 -0400
I agree that my response was snotty, but here's how I see it:
I spend a lot of time participating in usenet news: reading and writing. A lot of my professional life revolves around things I've learned a lot about through usenet news, and I hope I've managed to convey some of this information to other people. More than that, though, in discussing technical matters in usenet news it's often the case that all parties learn something. This is the traditional academic inquiry method at its finest. I think usenet news is great.
I don't at all mind people reading but not posting. That doesn't cost the full participants anything. Usenet news is a great resource, too. Dejanews is a wonderful database of knowledge, and I frequently do dejanews searches on technical topics I'm seeking information about.
But I really do mind people posting an article requesting that discussion continue off-line, or posting a request for information and expecting people to respond while not ever contributing to the newsgroup and being so certain about their future lack of participation and contribution that they're not even going to read the newsgroup for answers to their own question. I don't have enough additional information to know whether I overreacted or not in this particular case. I participate in usenet news because of its benefit to all concerned. Put it this way: If you don't ever read the newsgroup, then you're never going to help someone else with a question whose answer you know. It's like you're asking for help while refusing to help the next person.
When I was first an active usenet news participant (1985), there was a strong etiquette rule that one should read a newsgroup for a week or two before posting. I think that that's a good rule.
From: flaps (Alan J Rosenthal)
Subject: Re: SGI Security Question - Open ports
Date: 2 Oct 1998 20:59:14 GMT
Newsgroups: comp.sys.sgi.admin,comp.security.unix
>pls. reply without the NOSPAM. to my email
Nope. My article is for the benefit of the comp.security.unix and comp.sys.sgi.admin communities (and others who look for it). If you want our help, join us, don't just stick your head in and expect us to follow you out into the hall to help you in private. I'll answer your questions here. You'll receive my free help at MY convenience, not yours.
From: flaps (Alan J Rosenthal)
Subject: Re: Hacked system: Possible warning and advice requested
Date: 7 Oct 1998 16:10:39 GMT
Newsgroups: comp.security.unix
>One final request is to please send any response to me in email. I do
>not (at the present) have the time to check this newsgroup daily and
>search for specific replies,
I think I'm busier than you. We can compare details if you like.
For future reference, I think it's impolite to ask me to spend time on your case and not even be willing to do a simple dejanews subject search to find my reply. It is, after all, your problem. I'm spending more time on writing this message than you will spend reading it; I think you should be willing to spend the small amount of time to find the reply.