My first introduction to the Nostepinne egg (the little ball of yarn that you can wind with the Nosty) came at Cecilia's house early on in the week. Cecilia has the most delightful wool room at the back of the house with spinning equipment, fibre, skeins of yarn hanging up, and little Nostepinne balls lying everywhere like little Faberge Easter eggs.
The really handy thing about winding singles on a Nostepinne as because it creates a centre pull ball, once you've wound your ball you can then rewind it as a double ply ball (i.e. taking the inside and outside ends of your first ball and holding them together to wind a second ball). This makes it much easier to use for plying as you don't then have to worry about the inside unravelling more quickly (or in lumps) than the outside.
It wasn't until I started Googling Nostepinne tutorials for this post that I realised that, should you want to, you can also use the Nosty to wind flatter yarn cakes, such as you get from a mechanical ball winder. There's a great article on "nosting" here and a good YouTube tutorial here. I may refine my technique in time but for now I'm happy with my eggs.