Many people have read science fiction novels, and not all of them are regular SF readers. It’s a safe bet that not nearly as many people have read SF short fiction such as short stories, novellas, and novelettes. Reading short fiction is analogous to watching films. They do not require much of a time commitment and the entertainment value is high when the quality is high.
Using the definitions of the Nebula Awards, a short story is less than 7,500 words, a novelette is 7500 to 17,499 words, and a novella is 17,500 to under 40,000 words. Any fiction longer than that is considered to be a novel. These are not rules that every editor uses, however, and some prefer different word count guidelines.
If you want to support the creation of new short science fiction while enjoying the stories, the best thing to do is purchase electronic or paper copies, or subscribe to the magazines. The most popular U.S. print magazines that also have electronic editions include Asimov’s, Analog, and Fantasy & Science Fiction. Interzone is probably the most influential British SF magazine.
A number of SF anthologies have collected what each anthology editor considers as the best short fiction from each year. My favorite anthology is ‘The Year’s Best Science Fiction’, edited by Gardner Dozois, a long-time former editor for Asimov’s magazine. While some might view this as a conflict of interest, Dozois has been surprisingly even-handed in his selections, picking stories from other magazines not owned by his publisher.
Dozois’ anthology started in 1984 and has never missed a year. In 2005, Dozois edited ‘Best of the Best: 20 Years of the Year’s Best Science Fiction.’ This epic tome contains a foreword by Robert Silverberg, one of the most skilled writers in SF history.
My favorite authors who have written quality short science fiction include Charles Stross, Alastair Reynolds, James Patrick Kelly, Isaac Asimov, Eleanor Arnason, Michael Swanwick, Greg Egan, Robert Silverberg, Stephen Baxter, Robert Reed, Mike Resnick, Bruce Sterling, Kage Baker, Ursula K. Le Guin, Ken MacLeod, and Nancy Kress. I have also enjoyed reading short fiction from numerous other SF writers.