A familiar non-cyber example is a letter to the editor. So when the newspaper publishes the letter, they'll be protected by the implied license. Reasonable people would generally not assume that the author is allowing the recipient to forward the message to others. A newspaper posts something on its advertising - supported Web page. Reasonable people probably wouldn't assume that it's allowing readers to forward it to news groups.
Someone sends a message to a discussion list.
It's not clear whether reasonable people would assume that they're allowed to forward it to other lists. A lot might depend on the list's customs, and on whether the list is wide open or limited to only a few people. If I were the lawyer for a newspaper that didn't want its stories copied from its Web page, I'd tell them to put up a prominent notice about this.