I learned a few knots and even now when I buy a new pair of shoes I consult the site to see what lacing style would suit the shoe and my foot. (since different styles put different tension on the wearers foot).
I have to say, I'm happy it exists, it enriched my life in such a subtle way, this is the kind of content that the internet was made for in my opinion.
For single sheets, you can cut along the sides of the left and right edge which allows you to put your hands through and pull the duvet into the sheet, super easy and makes swapping the sheets easy.
There was a whole bunch of stuff, it's all incorporated into my lifestyle now so picking it out is difficult.