One of the members [of my] group has discovered there are blogs out there posting our messages. Anyway, I don't know what to do about this and don't think much can be done. What do you all advise your members regarding the blog situation?

If you can figure out which member is forwarding to the blog, remove and/or ban them. You can cite Guideline 11 as your authority (no re-posting of other people's content without their permission). A link to the guidelines is at the bottom of every Groups page.

The more difficult, and in my experience typical, situation is that the member doing the forwarding is using an ordinary email service (like gmail or Y!Mail Plus) and you can't readily identify them. You can specifically call attention to Guideline 11 among your group's rules, but I'm not sure it would help more than it hurts to make an ADMIN post to the group at large. That would depend a lot on the nature of the group.

For members asking you what to do about their posts, all you can tell them is that they must themselves use the infringement procedures of the blog site itself. Neither you nor Yahoo have the standing to force the blog site to take down the messages nor discipline the blogger. More about this in a bit.

Secondly, I have always been under the assumption that individuals posting to a group own copyright on what they write. I cannot find anything to verify this.

That is correct. Back in 1989 the U.S. joined the community of nations adhering to the automatic copyright provisions of the Berne convention, conforming U.S. copyright law accordingly. I like the "plain English" explanations here:

http://www.templetons.com/brad/copymyths.html

http://www.bitlaw.com/copyright/index.html

See also the U.S. government site:

http://www.copyright.gov/help/faq/faq-general.html#what

Does anyone know the correct legal status of our communications on groups pertaining to copyright?

Where an infringement lawsuit is concerned, I think the correct answer to this is a blanket "no". Until a lawsuit has been tried which hinges precisely on facts that match the case at hand, and hence provides a precedent, we're all just spouting legal theory. And even then, precedents /do/ get overturned from time to time.

However, specifically for a blog or other on-line resource in the U.S., there is a big short-cut in the law. The Digital Millenium Copyright Act (DMCA) provides a streamlined mechanism for handling infringement claims. It is still quite torturous for the hapless member who's had their messages stolen, but it avoids the need for registration, an attorney, and a lawsuit just to get the messages taken off-line.

See the "Copyright Policy" link on the bottom of any Yahoo Groups page to see how Yahoo handles "take-down" requests. Any U.S. based internet service must provide a mechanism that conforms to the provisions of the DMCA, but they don't have to make it easy to use (and they don't, notoriously so in the case of Google's Blogspot service).

I'm getting a lot of private emails about this. Gee, it would be lovely if everyone who has an opinion and feels compelled to share that with me were a lawyer, but they're not.

I doubt it would be that much less discordant if they /were/ lawyers. ;-)

If you search the archives of the moderator groups (see references, below) for "Copyright" you've no doubt found that this topic has come up time and again, usually with quite a range of stated opinions.

I did do some searches there and learned how these people set up the blogs and that it is a common problem not exclusive to us, but I didn't find anything on what to do about it.

That's probably because there is no simple answer. As a group member or owner you don't have the tools necessary to discover which member is forwarding messages. As a group owner you're powerless to act against the non-Yahoo blog host -- they are only required to respond to the Copyright holder -- your members. So your members much each go after the blog hosting company for their own messages. And possibly file a separate take-down for each message.

Though it sometimes seems tempting to rouse the troops to such a mass effort, I'm not at all sure that the results could ever be worth it.

I sent a message to our group that said basically there is no such thing as privacy anymore, be careful what you post, don't use last names, personal information, etc. I find that sad yet common sense.

Yes, but that's about privacy, not Copyright. If you're trying to keep something private, Copyright is just about the opposite of what you want. Although both subjects are often raised as a result of a re-posted message, in many ways they are legal opposites. Invasion of privacy is about keeping certain information private. Copyright is (generally) about who gets paid for copying a creative work. Said another way, Privacy is about the meaning of the words (the information), regardless of how it is presented, whereas Copyright is only about the presentation of the words, regardless of what they mean.

References:

Yahoo! Groups tips and tricks