Yes, it's always useful to explicitly state "copyright," though I doubt that means much to a lot of people.
Admittedly, most people don't fully understand copyright laws and issues. Technically, once something is created, a photograph is taken for example, it is automatically copyrighted in principle. Some people go the extra mile to register it with the gvt, but that isn't necessarily required.
But you're right, having it stated in the group would be helpful.
The purpose of the Yahoo groups? I would argue that the purpose is to share with people who are a part of that group within the confines of that group, not necessarily to provide content for people to take and pass around and post elsewhere.
Xtra, I'm not ragging on you. Honest. I've enjoyed the things you've posted. Maybe when posting content, though, you could acknowledge where you got it from - that might be polite, and I think most people would then be okay with that.
My irritation came from the "spammmmm" person. That was purely selfish, rude and inconsiderate. That type of person expects everything for free - gaining something, while offering nothing. I think the word "parasite" applies.
At least you're providing something.
Know what I mean?