Love this site. Bought their app a couple of years ago and started learning knots by tying them over and over on repeat during zoom meetings with a couple of lengths of paracord. Slowly building up a decent collection of knots!
I particularly like the comparison between similar knots that helps you understand when one is better than the other.
Interesting that the tag line is "world's best". I feel as though they usually go with something more quantitative like "fastest" or "most powerful", etc. "Best" obviously being completely subjective.