Walled Gardens in Mailing Lists

I've been thinking about this issue of Mailing Lists and ownership of the content that's published.

In most of the Mailing Lists that I'm on there is a culture that what the List!Mom says goes. This is considered fair because they are the ones putting the work into maintaining it and are the people who came up with the idea. They usually have a cohort of Moderators who people defer to in the second instance.

Now I've got a situation that I want to discuss, in-Fandom but not here *pokes tongue at readers*, about some culture issues that have developed within one of the emerging fandom's I'm involved in. One of my pieces of evidence comes from a Mailing List (ML) entry and the other an entry on an LJ. (Both different people and I have no intention of naming names because it really isn't relevant to the discussion.)

For the LJ, I'd either link to the post and take the link down if asked, or I'd ask because it's pretty clear that the poster owns the content.

On a ML though does the poster own the content? Do you ask them for permission? Do you cut and paste an entry? How do you reference ML posts? When can you use the post for reference without permission? Is a ML post public or is it part of a walled garden where the moderator/list-mom gets to say what goes? What about the fact that on a ML you don't sign EULA's (with their questionable legality), particularly not with the list owners directly and all behaviour on group relies on moderation/socially accepted behaviour?

And the other side of this is that I'm not actually trying to use this for an academic example (where I'd probably feel a lot more comfortable just using and sourcing) but for a meta-ing and possibly to raise the issues of cultural norms.