Flash fiction is very short fiction, typically either under 500-1000 words long.
We're going to post some of our flash fiction here but in the meantime you can see what we mean by visiting http://flashfictiononline.com/main/
Flash fiction differs from a word sketch or vignette because it must be a self contained story that comes to a satisfying conclusion; in other words it needs a beginning, middle and end.
For many, me included the first piece of flash fiction preceded the digital world. This story is usually attributed to Ernest Hemingway 'For Sale: Baby Shoes, never worn'. See also Drabble.