日本語人 (romanized Nihongozin) is an iPhone app from the team behind the incredibly popular Japanese language-teaching YouTube 日本語の森 (Nihongo no mori).
Nihongozin's goal is to become an online community for Japanese speakers and learners from all over the world. Unlike other social media apps, this one allows you to see posts by everyone using the app without needing to follow or friend them.
Users upload images and short videos from their devices or link entire YouTube videos to share with each other. Users can upvote, downvote, comment, and re-share each other's posts to their own profiles. The profiles themselves are also specialized for Japanese speakers, letting you choose the highest JLPT level you've passed (or the level you're currently studying to pass), or indicate that you're a native speaker.
While the entire app and its posts are in Japanese, Nihongozin contains a function for Japanese—or more specifically, kanji—learners. When reading a description for a post or comment, users can click a "Furigana" button (or do a long press on the text) to show it above the kanji.
A couple of caution points. First, at least at the time of writing this, Nihongozin requires users to share their location, so you can view other users nearby, converse with them privately, or block them if you choose to. (This is social media, after all—others can see your location unless you block them.)
Some users have a special ガイド (guide) marker indicating that they're available as guides for hire. If they are, you can also see their available times, rates, and location. If you're looking for a tour guide or Japanese tutor, for example, you can find them through the app. You can also be a guide for Japanese folks visiting your city. Needless to say, whether you're looking for a guide or offering to guide others, be extremely careful. Other than the blocking option, the app provides no protection, and no payments are done through the app itself. Posting on Nihongozin is like creating a listing on Craigslist.
Safety aside, we wish we'd had this app when we were studying Japanese in our younger days. It struck us as a great resource for learners who don't have many Japanese-speaking friends. Hope to see all of the sakura and tea pics from your trips posted there!