Duolingo is a learning game. It should not be treated as more than that. The dream is that all we need to do is play to learn a skill but Duoling has not found the secret sauce yet so it will not teach you a new language all by itself. You need to use it along with a teaching system.

What's a bit distubring is that it is being taunted as a complete system for beginners.

I think it's a disservice to new solo learners since eventually people give up and have not learned as much as they could have given the time and effort put forward.

I think Duolingo has a place but it should be an aside to a proven learning system not the only tool.