Total hours played??
I read on wikipaeda that because duolingo is so well put together that 34 hours of lessons here equate to a first year college semester of 130+ hours so that being said i would love to know how many hours of learning I have done.
Would there be any chance of this on an update and would any one else like this type of information on their profile?
I would love if they could do this, because I've thought of other way in which Duolingo can use that time to give us different feedback. But I didn't put too much thought to it because I know at least for me, I get up to eat and do something right in the middle of a lesson and even when actively working on a lesson I will spend time doing web searches (that may be fruitless) for grammar rules, spelling, conjugations, etc. So I'm sure just about everyone is like me to varying degrees. So there really isn't any way to really say how much time a user is spending on Duolingo. I would say that study was either as rocko2012 suggested, an estimate or there was a more controlled method of measuring how much time was spent.
Now if somehow they could measure the time, they probably wouldn't release that information at least individually because some might feel alienated by the knowledge that given their level and time spent would give an average level per time and would make some feel as though they are taking longer than "necessary" and therefore resulting in a discouraging effect. Duolingo would want all to try.
Personally I would love this information too. If you share your progress with someone you can see the times and dates you logged in and the equivalent number of XPs you've accumulated for that day. I've gathered 10XP =1 lesson. I saw somewhere that 1 lesson takes roughly 10 minutes. So you can estimate the time you've spent. But I'd rather have it directly on my profile or activity sheet.