Craft is about skill and technology and as such we judge it rather objectively because standards are often codified and do not contain those tricky artsy terms such as meaning or symbolism etc. which is why it is easier to understand. Art is about knowing what you want to say and being successful at saying it. We judge it subjectively. It is harder to understand because we have to think for ourselves about meaning etc. and have to spend time learning the language of art. Both art and craft take an extraordinary commitment to do well.
In 2006 I wrote
If you create or find your own fibre, pattern, needles and, or use them in an unconventional way you are clearly an artist. Another way to determine if something is art or craft is to ask the question why? Why are you knitting this item? Is it to serve a purpose? If you knit a sweater because you are cold. You are a crafter. On the other hand, if you are making a profound statement by knitting the item then clearly you are an artist.
A search engine yielded this website: http://weburbanist.com/2009/02/06/knitty-gritty-15-works-of-knit-art-and-graffiti/
Interesting, if only for the pictures.