So is a better idea to produce screen casts instead of writing blog?

If the screen cast includes audio narration, no. From the the article: "the study determined that it is the dual action of speaking and hearing oneself that has the most beneficial impact on memory."

The person doing the learning needs to be speaking out loud. Screen casts with narration would be worse in this regard because the viewer wouldn't be able to speak and also listen.

Parent says

> ... to produce screen casts ...

Not "to consume".

Then it is better for the producer, but at the cost of denying the consumer this benefit.

"Repeat after me: ... "

Win / win.

If the idea is to cement your knowledge by passing it on to others, I don't know what would be superior.

In both cases you'd need to synthesize your learning and put it in your own words.

I do similar to the blog approach by writing thoroughly documented and demonstrated answers on Stack Overflow. Sometimes (including yesterday) I need to go back and review my conclusions. Yesterday, I was looking for whether I should change some raise statements or not. Since I concluded that the old statements are deprecated, I went ahead with the change, and it was approved as I submitted it.

I've also taught in the classroom, but since I'm working from what I already know (and encountering things I've forgotten) I don't know that it's actually better. It's just different.