Nintendo has released a web based version of MiiVerse. You are now able to use a computer or a smartphone to get access. Ironically the 3DS's web browser and the Wii U browser ( I dont see why you would try to use the Wii U Browser) do not work with the MiiVerse.  Instead the PS Vita Browser's is capable of allowing you to use MiiVerse on it. It's great when companies support each other like this.