A new trailer for Unravel explains the inspiration behind the game and Yarny, its hero. There's a post on the same topic on the Unravel website with more from Martin Sahlin on the character. Here's a bit:

Yarn means a lot of things in Unravel. It represents the bonds between people, the red thread that ties everyone and everything together. It stands for love, and Yarny is the manifestation of all of those things. Tethered to something important at the start of the game (and trying to make it to the end without unraveling), Yarny is a helper – a positive force.

I really wanted Yarny to be brave, and to accomplish great things despite being so small. I hoped when we were making the game that Yarny would be empathetic and relatable, and based on your support, I can see that Yarny is already reaching people.

We hope that you’ll love playing with Yarny when Unravel comes out on February 9, 2016.