Everybody uses them, don't they?..Well Davy and I only very rarely use them ,but nonetheless it's a good skill to practise if for nothing else than helping you achieve good knife control..We often hear people telling us how we should use feathersticks when it's wet to help us light a fire. Davy and I have went out in the pouring rain to try just this, we had no shelter, it was twilight and we needed a fire fast, so we cut some nice dead ash and split it with our leuku's and started making feather sticks, after about 10 minutes, not only were we soaked but so were the feathersticks resulting in a non starter for the fire..We quickly gathered some birch bark and had flame in less than 15 seconds!! Lesson learned, if you want a fire quickly, forget feather sticks, go straight for natures own firelighter...
However if you do want to make them, a few things to remember, use a wood with a long straight grain, no knots and use light knife pressure, also small feather sticks work better than large ones, and remember to make each feather different sizes, you can see in the picture below I have carved some thin and also some thick as this will help your flame establish.
One last thing you don't have to shave the wood to feathers, you can just keep splitting the wood into long thin strips as thick as a matchstick or thinner and use these, they are just as good as feathersticks, long thin wood strips are called fire-splinters or fiddlesticks!
( Update 25.12.2010, with regard to the fire splinters/fiddlesticks mentioned above, I have just watched the Desert Breakdown episode of Dual survival and noticed Dave Canterbury making these, see, we are not the only ones who like them!!))
