It should be very simple to implement, just don't post it on the asciinema.org. It would double the user base (at least) , think of all the people willing to share their terminal activities to only people they know..
Honestly, it would be better for you @sickill if it was a small amount monthly. $5, $10, even $20. Oh my goodness this would be such an incredibly useful feature, and it would be worth giving you an incentive to keep working on asciinema :)
That's wonderful news! I am very thankful for this feature.
It appears that you did not introduce any paid model for this. I recommend you also think of a way to monetize asciinema's usage in the future to raise funds for further development. It's a cool project!
@hardipe Enjoy! No, no paid model this time. Maybe some day, we'll see. As for private asciicasts I realized that this is a really essential thing, and everyone who wants to try asciinema shouldn't be forced to auto-publish their first recordings.