There is a possibility that a The World Ends With You sequel will be getting announced soon. It could be coming out for the Nintendo 3DS, Nintendo Wii U or maybe even neither.
There is a teaser site from Square Enix that could possibly be related to a sequel to The World Ends With You. The way the text is written on the website is the same as in The World Ends With You. Plus, two of the character designers are Tetsuya Nomura and Gen Kobayashi, which are the same people who worked on the first game. There is a countdown on the site, so I guess we have to wait 6 days before the site opens. You can check the website HERE.