Primer by Google

Primer is an app by Google which is designed with an average of 5 minutes lessons targeted to learn new marketing skills fast and easy. The lessons falls mainly into 4 categories as;

1. Advertising
2. Content
3. Measurement
4. Strategy

And of course the marial UI gives a nice and smooth navigation between the lessons.

So, try this and gain your online marketing skills even one lesson per day before you goto bed.