I did promise to update people about the status of microfiction and what I've found out about its eligibility for certain awards. As stated before, yes, you can nominate it for a Hugo Award for short story.
However, unless it meets the minimum qualifications outlined here, namely payment of 3 cents a word and at least $50, it DOES NOT start your Campbell clock.
Just passing word along.
Some people this year who are eligible for the Campbell Award and whose writing that I like (other than my clients):
Aliette de Bodard