In the scientific and medical communities, the technical name for using one's finger to extract boogers is rhinotillexis, and doing so compulsively is termed rhinotillexomania. The act of eating the resulting harvest is called mucophagy.
There is an Austrian doctor who has gained notoriety by advocating the picking of one's nose and the consumption of the resulting bounty, particularly in children. Dr. Friedrich Bischinger, a lung specialist working in Innsbruck, would have us believe that people who pick their noses with their fingers are healthier, happier, and more in tune with their bodies. His argument stems from the notion that exposing the body to the dried germ corpses helps to reinforce the immune system. The good doctor feels that society should adopt a new approach to nose-picking, and encourage children to take up the habit.
Dr. Bischinger has been quoted as saying (in an Austrian accent), "With the finger you can get to places you just can't reach with a handkerchief, keeping your nose far cleaner. And eating the dry remains of what you pull out is a great way of strengthening the body's immune system." He then added, "Medically it makes great sense and is a perfectly natural thing to do. In terms of the immune system the nose is a filter in which a great deal of bacteria are collected, and when this mixture arrives in the intestines it works just like a medicine."
"Modern medicine is constantly trying to do the same thing through far more complicated methods, people who pick their nose and eat it get a natural boost to their immune system for free."
This theoretical boost comes from the fact that boogers are chock full of bacteria which your body has shuttled out by way of mucus. Mucus lines many of the pathways into the body's delicate innards, and creates a surface which is like flypaper for bacteria and other particles. Once stuff becomes mired in the goo, the loaded mucus is slowly escorted out by tiny hairs called cilia which sweep the undesirables back out the door. In regards to the nose, when this exiting mucus becomes dry, boogers are produced.
What our good Dr. Bischinger doesn't tell us is that nose mining can be a dangerous pursuit. If the skin inside the nose is broken while picking away, the veins in that region are situated in such a way that sometimes an infection can migrate inward to the base of the brain and inhibit the blood flow, a serious condition known as cavernous sinus thrombosis. This condition can also be caused by squeezing zits on or around the nose. Because of these risks, the triangular area of the face from the corners of the mouth to the bridge of the nose is referred to in the medical community as the "danger triangle of the face."
Risks aside, can the immune system really be reinforced by introducing germs into the gut via boogers? While the unpleasant notion may have some scientific merit, it is not based on any formal studies. For this reason, I propose a clinical study where each test subject is given real boogers or placebo boogers for a period of several months, and each group's susceptibility to disease is cataloged during that time. Only then can we know with any certainty.