Broomstick lace is a crochet techniques that involves yarn, a crochet hook and a large dowel or knitting needle. After a foundation row of single crochet, a large loop is placed on the dowel or knitting needle and continued across. The work is never flipped in broomstick lace, it is worked back and forth as in Tunisian Crochet.
Broomstick lace is great for sweaters, shawls, scarves, hats everything. And once you get the hang of it, you will realize how quick it is. It provides a nice stretchy fabric with excellent drape which a lot of people don't expect with crochet. I prefer to use thin gauge like fingering weight or sock weight yarns for crochet, dk weight at the largest unless I am working on an afghan.
Here is a quick pictorial/tutorial: