Memrise is a flashcard program with community created courses. They have lessons for all level (from beginner to advance) on all kinds of topics (languages, humanities, computing etc).
You can use the program through their website, or app. (I personally prefer the website, but the app is good for practising Japanese on the go).
You don't even have to use other people's courses, you can make your own flashcard decks. And you can keep them private, or make them public for others to use.
I love using Memrise as a creator and a learner. I love it because it's easy to use, it's fun, motivating and helps you learn!
They're constantly trying to improve their program, including the spaced repetition software.
Also, IT'S FREE! You can buy a years subscription (they constantly bother you about it on the app), but you don't need it to access any of the courses or reap the benefits.
Japanese Talk Online Memrise Courses
Of course I've made courses! They started with the hiragana and katakana through vocabulary because all the other courses were just learning the kanas (which I didn't think was very effective).
There are various lessons helping users practice beginners grammar, anime related vocabulary and grammar, vocabulary and kanji for the news, and JLPT lessons.
Have you ever used Memrise? What are you favourite courses? Do you prefer to make your own or use others?