Markings; defined as etches, watermarks (both real and digital), trademarks, signatures, and symbols that have been used by one particular person, group, or manufacturer to make sure their stuff isn't copied straight and you'd know that it's genuine. In RevanAC's case, it was the primo "RevanAC" on his artwork. Many companies do this however, such as Surefire flashlights (they put marks on their stuff), Chinese manufacturers make clones that look almost exactly the same thing.
To be honest, I wasn't really paying attention to this thread, until I saw when his work was stolen.
I know how it feels to have my art and photos stolen over the internet, even my usernames. Yes, at one moment you're all like "WTF HOW CAN THIS HAPPEN TO ME WTF?!". But, there's always a proper course of action that can take it down, and I'm sorry that your artwork was stolen as well.
It's really a same that it happens, but you wouldn't imagine how smart felt when their ForTwo was copied by some Chinese manufacturer. I'm currently finding someone who's willing to put a watermark on my stuff so that way nobody can log onto a forum and say "Look what I got! I've been owning this thing forever and it's my work!" Sorry for not being clear enough, I thought it was.