DS Flash carts have plenty of useful applications, most of which involve user-created (and perfectly harmless) "homebrew" applications for Nintendo's original dual-screened handheld. But the most popoular flash cart, the R4, is mostly used for another purpose: piracy.
Pirating games with the R4 is as easy as downloading a 3MB game and dragging and dropping it into the cart's interface. And it's that ease of use that caused it to become so overwhelmingly popular.
Nintendo's been trying to do something about it for years, and now the R4DS has finally been banned once and for all in Japan, according to Kotaku. The device was already banned from sale, but now it's illegal to import it as well. No doubt some people will miss using the R4 for homebrew and other purposes, but this might be a good thing for game sales overall. What do you think?