I started using duolingo a few months ago. I found it randomly on google chrome , while searching for tools that could help me learn french and german. It was by necessity that I searched, because I intend to learn both languages , and probably another (swedish maybe) , in the next few years , so I may have a greater job mobility /opportunity , and also to be able to ask for a beer and a coffee when traveling (xD).
Well I must admit at first I had no hopes it could work. It took me many years to fully understand english, many more to speak it in a decent way. But after some months my french is getting better , and I can understand some things in german already ( I could not even read one word ) .
And since the last announcement my hopes got higher. Not only new languages will be added ( swedish!) , others will be improved , probably video translation, new tools!, possibility to directly chat with natives! ( I will gladly speak portuguese to anyone who wants to learn it xp ). Duolingo might not quite get the impact they can make in someones life, but they are surely helping me.
If I can I will help in the process, even if it's by speaking portuguese to other duolingers.
tl;dr : Just me saying thanks.