One of my (very) short pieces of writing appears on Nanoism. It is, in fact, only one sentence long. Nanoism publishes tiny stories on Twitter and on their website. My story is viewable at nanoism.net/stories/505.
Some of my recent favourites by other writers include #492 by Katherine La Mantia (nanoism.net/stories/492); #499 by Tom Byers (nanoism.net/stories/499); #483 by Eric Boyd (nanoism.net/stories/483); and #482 by R Gatwood (nanoism.net/stories/482).