Answer to "Why to Forge":
Wire jewelry makers 'forge' wire for several reasons as it shapes, stretches and hardens any metal used. One example can be ear wires: if a 20g round wire is used to make an ear wire, after the initial shaping, the curve that goes through the ear can be forged with a chasing hammer to flatten it, adding not only an artistic look to the ear wire, but also hardening it into the round which for some people can help to prevent it from slipping out of the ear easily.
When some of us make jewelry using heavy gauges, like 14 or 12, we use soft wire because it is easier to work with, and by 'forging' it, we not only add to the shape, but also harden the design into place. For an example of forged heavy wire, I invite you to see this piece on my personal gallery page: Cougar Creations. This set was made using 14g square, dead soft wire that I shaped first, then forged using a chasing hammer, which gave the slight rise to the earrings (as hammering the metal slightly stretches it, causing it to rise). Sometimes folks turn the piece over and pound it again to make it flat, however in this particular case, I used the rise to add dimension to the design.
If you would like to experiment with forging, you will need a chasing hammer, a steel anvil or bench block, and I would recommend copper wire to play with (An inside tip, in my upcoming Intermediate DVD series, there is a project that introduces you to forging.) It is also very important to wear eye protection while forging, like glasses, safety goggles or optivisors!