I read in a book that there was a right end and a wrong end to fiber - an end you should draft from and the, well, the other end. I haven't found the book reference (perhaps I will find and post the title later), but I did find a reference on the Web. Check out http://www.rollinghillsalpacas.com/fiberspinning.html
Some great information on alpacas, and the site references The Joy of Handspinning. With drum carded or commercially processed fiber, you should draft from the end that pulls out more easily - that simple! At least it seems to be...I've got fiber to practice with, and I'll post my experience trying to detect a difference.