Multiple course streak issue
I'm currently on a 4 day French streak, and a 3 day German streak according to the android app.
Online the streak counter says 6 days, no mater which language I'm on, and the emails/notifications on my phone also said 6 days for both languages.
The streak counter on the website is the general streak, i.e. the number of days you have done something in any language, not the individual streaks for a language.
But I did find it a little odd that Duolingo recently sent me an e-mail telling me that I should keep my 160-day Danish streak...
Check out the Wiki, when in doubt it maps it out. Go from the FAQ http://duolingo.wikia.com/wiki/Frequently_asked_questions and choose the general tab the choose "streak" from the contents menu (or just scroll down). :)