Dear Duolingo, a few suggestions....
Dear Duolingo Team,
I've used your app on and off for about two years and commend you for creating a cheap, global platform for learning languages for so many people. It's the great side of the internet and serves a genuine positive social cause. Bravo.
However - Crowns, Health, the payments system, the differing incentive structures of the desktop vs mobile apps, gems vs lingots.....these are all fairly shaky areas. Can I suggest you:
a) stop pursuing the business model of a 'free' but addictive game used to get kids to pay with their parents' credit card eg. Work on a donations basis, or a recommended fee maybe? Waged people $50 per year, students/unwaged $20, other $5...lock off half a course if you don't pay maybe?
b) beta-test changes to the platform internally more.
c) think of expanding the online resources and references eg. keep hint and notes compiled on the page. This type of resource is actually scarce on the web!
All of these suggestions are coming from a strong supporter and fan.
I wish Duolingo would listen to posts like this. A while ago they decided to change the site and make it more effective and function better, however, I just see more gimmicks and things. Course quality has significantly reduced and are now being released without any plans to add audio. Originally Duolingo was the most effective site I had come across. Now I find it harder to stay focused and am slowly switching to other resources.