How are lessons put together?
It seems to me that a lot of phrases contained in lessons are not exercises on the lesson's subject at all. One example out of many I've seen: when doing the "reflexive verbs" lessons, the sentences simply contain words that are used to form reflection ("mich", "sich", etc.), but are not actually using reflexive verbs, e.g. "Das ist zwischen mir und ihnen".
I have a feeling that the Duolingo system is using some kind of automation to decided which phrases, out of a whole database of them, should be incorporated into a lesson, and that it's not quite successful at doing so. Can someone from the team give us feedback as to how this system works and if you're aware of its faults and how you're planning on improving it? Duolingo still rocks, by the way, and I'm completely addicted, so take my question as one looking to improve an already smashing application.