Here's a brief rundown of the yarn weights:
Carrying - A fine yarn that usually comes in low yardage to carry along with another yarn to add depth to the project.
Lace - A very fine yarn that can come in either sewing thread size, to a bit finer than fingering weight. Of course, used for lace knitting. It's really the hardest to classify , becuase there are so many varieties: gossamer to all different thicknesses.
Fingering - A light yarn most often used for socks and Fair Isle designs, but can be used for other projects, like hefty shawls.
Sport - A moderately fine yarn used for just about anything, socks, sweaters, and some afghans. It's often used for Norweigan 2-color knitting designs, but can really be used for anything.
DK (double knitted) - Just about worsted weight, in fact, almost identical to light worsted. Can be used for anything that calls for light worsted/worsted weight.
Worsted - A medium yarn that can be used for everything like socks, scarves, shawls, afghans, sweaters, all projects. It's the most widely used yarn and most widely available. Light and Heavy worsted are just basically worsted, I never pay any attention and just use worsted.
Bulky - A thick yarn used most for scarves, hats, afghans and coats. Not really used for pullovers, because they'll be too warm. If you make a sweater, be sure to add extra stitches, because the inside measurment will be smaller than the outside measurement.
Super Bulky - A very thick yarn, used for afghans, etc. Anything you want to work up in a matter of hours/days. Some super bulky yarn is only classified as such because it has a fuzzy halo and needs a large gauge to show it off.
That's what I could come up with! Hope it's accurate.