Email prompt to continue learning is flawed
I really like the idea of an email reminder to keep at learning, but the timing used is flawed. I can be using Duolingo before the setting time (11.00am in my case) and no sooner have I finished my session I get an email to keep at it. As a retiree I can spend more time than most, and sometimes I am on the computer most of the day. There may be three or more sessions when I am on Duolingo. Then each morning regardless of the last time I was logged on to Duolingo, 'bing' an email reminding me to keep at it. Very annoying after a while.
You didn't properly read what I posted. I am well aware how to change or disable the email alerts, what is in error though is the way the timing is calculated. Let's say I am using Duolingo at 9.00am and my alerts are set for 11.00am. I can quit my session after 1 hour (10.00am) and at 11.00am an email arrives saying I haven't been back for 24hrs and I need to keep at it. Clearly this is not the case. The cookie or whatever is used to keep track of my progress needs to be modified.
Or maybe, and I feel this is more likely, the email is not based on my last time but is just a simple clock-timed mail out. In that case it is next to worthless and should be removed or fixed with an actual time used since last visit basis.
No doubt your site keeps information about each login, how else can users stay logged in between sessions.