Duolingo is what finally got me moving forward with German. I had used other apps, books, and audio courses, but Duolingo motivated me to stick with it. It's almost as addictive as a game. They have a really good variety of exercises and activities so it never gets boring. The lessons are short enough to be completed quickly, and the graph showing your progress encourages you to keep on going. I like the ability to connect with friends who are also using the app, and the daily email reminders are helpful, too. I like it so much that I started using it for the other languages that are offered. I'm reviewing Spanish, Portuguese, and French, and finally getting serious about Italian. I hope that they add some other languages in the future. I'd like to see Russian or Polish. The only area where the app might be improved is in providing a bit more grammar background, but I use books for that. This has been a bigger problem for me with German, mainly because word order and using the correct endings for determiners, nouns, and adjectives can be a challenge.