See, boogers spend all day catching dirty and dust and stuff that your nose wants to keep out of your lungs. Why then would you eat the dirt? That simple idea has been what has always kept me from eating whatever goodies I pick out of my nostrils.
Meanwhile, in reading this thread I laughed so hard I HUFFED a booger -- one of those crusty front, gooey trailer booger comets -- right out of my nose at high speed AND NOW I CAN'T FIND IT. I have a meeting in ten minutes and SOMEWHERE, possibly stuck to me, is a booger. I just know it.
We joked with a doctor about this today; he says it's not about the crap your nose catches, it's the fact that the mucus that builds around it is your immune system response that defeats a lot of air-based germs, and "supposedly" ingesting that part is like taking self-made antibodies.
He then joked that it's been the joke around the office and he still, out of sanity sake, didn't think he'd recommend it.