The Nintendo eShop is the name given to Nintendo's online stores for the Nintendo 3DS, Wii U and Nintendo Switch, the successors to the Wii Shop Channel and DSi Shop for the Wii and Nintendo DS, respectively.
You can purchase and download software and games using it, including "Virtual Console" games. These "Virtual Console" games are rereleases of classic games, including some Zelda games, such as Link's Awakening DX, The Legend of Zelda, and The Adventure of Link .
Nintendo had an offer for 3DS users who bought a console before the 2012 price drop, that was dubbed the "Nintendo 3DS Ambassador Program". People who accessed the eShop or performed a system update before 11:59 EST Aguust 11, 2012, received 10 free GBA games and 10 free NES games. Among these were both NES Zelda games and The Minish Cap.