There's actually quite an open market for imitations of great art. They're not nearly as valuable as the originals, though, because painters like van Gogh created astonishing works of art and part of the value is being able to gaze upon original proof of astonishing human achievement.

I would never repaint van Gogh, because I'd rather paint my own things. On the other hand, if I were to want a Thomas Kincade painting (for some ghastly reason), I'd definitely buy the cheapest reproduction I could find, because the original painting just wasn't that valuable to begin with.

... and that is fine as long you let people know that it not an original van Gogh.

Unfortunately, you picked a bad example: a painting is a finite resource -- there is only one physical painting painted by the original artist. A painting cannot be "copied" with the same veracity as software can be (bitwise, which in the case of software becomes piracy) and any attempt to pass a "copy" of a painting as an original is forgery.

Classifying any work (art/software) as a rip-off requires defining the very fine line between fair-use and unfair forgery. When it comes to artistic endeavors (as in "design"), you'll have more luck defining the position and velocity of an electron around a nucleus than delineating that fair/unfair boundary.

I think this is a bad comparison. Yep, if I repaint Starry Night, I will not be Van Gogh; but the case here is different. dcurtis' idea was public influencing. The idea was a blogging paradigm which would effect the writing approaches of the people. It was a great idea, but it's different from a personnal artwork. It has a broader domain than it. I think the society is allowed to use the idea. I agree, perhaps obtvse creator could do a little innovation and use a little different CSS and HTML design.

If you paint Starry Night from scratch and hang it on the wall at a strip club, that would be a parody, and would constitute transformation of the original.

But if you are saying only a few people can see it, then you shouldn't be offended if someone makes a copy available to world.