According to Japanese newspaper Nikkei, Nintendo will start offering trailers for new games as well as "free mini-games" on smartphones. Some of the information gets a bit lost in translation, but the way Nikkei describes these mini-games sounds a lot like a standard demo. The content won't stop there, however, as Nintendo will also offer information on the game's story and characters.
Operating systems aren't named, but it's a safe bet that iOS and Android will be among those featured. Nikkei reports that Nintendo will be making an official announcement later this week and, as Kotaku points out, Nikkei has a good track record when it comes to Nintendo rumors.