MONA was the first Japanese cryptocurrency. This coin was first created in 2013, and as such it's a pretty old asset that still has a few loyal followers remaining. Most of them are left checking the project's bitcointalk thread hopelessly for updates. Unfortunately, it doesn't really do much else besides be a coin.
It has no other features that set it apart, it has no roadmap, it has no real use cases, and the development team has long since abandoned it. It uses the Lyra2RE algorithm, and it can still be mined should you want to try doing so though. While it has no social media there is a website, barely. Buyer beware on a MonaCoin investment.
You can buy MonaCoin on a surprising number of exchanges considering what it is, and it has a good bit of volume as well. The most popular trading pairs for this coin are the Japanese Yen and Bitcoin. I was surprised to see this one listed on Bittrex as well as newer exchanges even. No doubt community funded applications.
To store your investment you can use the official desktop wallets or you can also store this asset in the multi-crypto mobile wallet from Coinomi on your Android phone if you wish. Or by using Bluestacks Android emulator on a Windows desktop. I would honestly opt for the mobile wallet out of fear of a bug in the official wallets that may never be fixed due to the lack of a dev team.