There's no need to get this technical about it. Its reasonable enough to assume that you're free to copy and use my comment here as you please and that I don't

There's no need to get this technical about it. Its reasonable enough to assume that you're free to copy and use my comment here as you please and that I don't give a damn about that. I doubt anyone will make a fuss over something like that. It's basically fair use and you're example takes it too far amd isn't very realistic. I do agree that people should use a copyright mark if they want to claim their rights but in most cases it doesn't take a rocket scientist to tell if something like a blog post or comment author is going to throw a fuss over copyright. And if you happen to get it wrong then they'll ask you to take the infringing work down before any lawsuits come out (in most cases).