Suggestions for making duolingo more community friendly
This is not so much of a formal suggestion, but an expression of certain quirks that feel to me that they could be even better.
One thing I notice is that when a mistake is made, the option to report that duolingo made a mistake is offered, but it makes the assumption that the user thinks that he was marked wrong incorrectly, and knows the correct answer. Sometimes I find that typo detection lets me off the hook when I know I made a mistake, or I simply want to make a suggestion for improvement on a particular card. So a generalised "comment on this card" feature seems better to me.
Infact sometimes I want to make a comment on an entire lessons, so if there were automatically comment/dicussion threads on each lesson series, that could be cool. For example I noticed that with the German Plurals lesson I was able to guess most of the type-the-english-sentence cards simply by putting everything in plural form by default since that was what the lesson was all about, so mixing up the sentences with plural and singular components might fix that.
If you set up these tools right, you can get your community to do a lot of your work for you :]. Perhaps making discussion threads all over the place would be too messy and I don't have any good suggestion at all, but I at least thought this would be worth mentioning.