Cloning is perhaps one of the greatest breakthroughs science has ever brought the human race. Its potential to help the world has potential, as does its potential to utterly destroy it. The question is whether or not mankind is responsible enough to draw a line at which cloning must stop and then not crossing that line. Of course, this being mankind, we will just clone away and not even worry about moderation, as it is the nature of society to carry things to extremes in the modern age .
Cloning could possibly cure such things as world hunger, wool shortages, and many other nagging social problems. For instance, using genetics we could conceivably make some super-cow which produces the same tasty, juicy beef as a regular cow but consumes much less vegetation. That super-cow (affectionately named "Test Cow #12-TH3123") could then be cloned again and again, providing such useless nations as France and Belarus with plenty of fresh, tasty, semi-American super-beef.
The application of course would also apply to fruits, vegetables, and nuts, which fall under the meat group. The ability to clone the perfect pineapple is a dream several scientists have worked towards for many years, along with the drive for the ultimate apple tree. These plants, when cloned, would make wonderful things such as canned pineapples and Applesauce.
And don't forget the blind! They're people too! And as people, it is their right to be given seeing-eye dogs, dogs that act as eyes, even though they can't read or decipher color. The greatest seeing-eye dog (named Bluto and owned by a man named Joseph Corinimpksi) could be, of course, cloned, and then every blind person could have a great seeing eye dog, provided that they were trained.
The dangers fall in cloning humans or near-humans, such as gorillas or really smart chimpanzees. Since human beings are sentient, there would be another working consciousness created in the cloning process; initiating one of two possible outcomes. In the first outcome the clone and the person cloned would stumble through a series of semi-amusing mistaken identity situations, yet would in the end work out their differences, a la Multiplicity. The second outcome is that the clones would rebel against us, the natural humans, and then take over the world, making us their slaves. This would be less fun.
Of course we should also beware of the possible dangers of cloning. The health detriments of cloning could unravel the fabric of our society. Possible viruses could emerge from the process, or extremely virulent strains of cancer. And perhaps the worst of all, the deluge of Parent Trap-themed movies would cause mass-suicide, which would then create mass labor shortages, and in turn a large economic depression, followed by cannibalism and ultimately a return to prehistoric lifestyles. That is bad; we should be careful not to let that happen.