I'm a huge fan of flash fiction. Keep your purple prose and your keen detail and inscrutable plot twists, I want to get to the heart of the conflict.
Flash fiction = Great Stuff.
Of course, I'm a big fan of haiku as well, and the forms are suprisingly similar. Each of them is a condensed form of story-telling; a vignette, a brief scene, from which much significance can be derived.
We don't receive enough flash fiction at The Battered Suitcase, and we'd certainly love to see more.
I do think that sometimes there's a big disconnect when it comes to what flash is and what it isn't. Just because it's short (generally less than 1000 words) doesn't mean it doesn't require all the elements that short stories require. Flash also needs a plot, rich characterization, conflict, and some kind of resolution -- even if it's a somewhat more ambiguous one. The tricky part is to create this condensed literary experience and still keep it rich.
Traditionally, haiku requires a 'kigo'. This is a word that drums up a specific seasonal tone and all the feelings, smells, sounds, -- everything that comes with it. A talented haiku poet can choose a kigo so laden with cultural meaning, that the reader can taste the fruits that ripen in that season. The right kigo can invoke the bitter chill of late winter, the damp of spring, or the sound of summer crickets in August. The poet has chosen a word that evokes very strong and very universal memories in her culture.
That's exactly the kind of careful choice of words that lends richness and history and characterization to a flash fiction piece and gives you room to play with your plot. Cultural universal terms can nail the reader right into your story, without paragraphs of backstory or description. Chose your terms carefully. Make them earn their keep.
For those who'd like to strengthen their flash fiction, I recommend you familarize yourself with some of the traditional kigo used by haiku poets and then play around a little with your own cultural universals. Modern Westerners are not as closely-lived to nature, but there are 'seasons', experiences and events that we experience universally: first day of a new school year, first day of summer vacation, the winter holidays, the first warm breeze of spring. Find the most universal elements in your settings and characters, and then play with the words you use to describe them. Brainstorm a little. And don't be too proud to use a thesaurus.