Let me know if this question is too abstract, but what exactly is this group going to consider sci-fi? I mean, you've got examples like Star Trek and et cetera, but what about series like Shadowrun, which contain both elements of sci-fi and fantasy?
Where do we draw the line... moreover, is there a line at all? I look forward to your answers.
Hard SF - Centered around real Science fact. Maybe with some slight conceits for the sake of making a story work. (Such as the existence of Faster-than-light travel) Example: The Moon is a Harsh Mistress by Robert Heinlein.
SF/Pulp SF/Space Opera - Less than perfect Science, but still basically based on things that could actually happen. Example: The Matrix, Sunshine, Aliens.
Sci-Fantasy - Hey, you got chocolate in my peanut-butter! Example: Star Trek (Arguable,) Star Wars, Buffy, Blade.
Fantasy - A complete absence of technology, no science, out-and-out magic. Example: Lord of the Rings, Pokemon.
The usual distinction is that science fiction is realistic (what might happen), whereas fantasy is firmly implausible. So for example Star Wars is fantasy (because there's no internal coherency), and Fafhrd and the Gray Mouser is science-fiction (because apart from the odd supernatural element, it has believable characters and world-building).
Yes, I know you might object to my examples. The point is that it's not an objective distinction. There are also works designed to remain ambiguous, not to commit to one side or another. A couple of examples that come to mind: Jane Lindskold's Through Wolf's Eyes (medieval setting with old powerful artifacts: stranded colonists or fantasy world? later volumes in the series do commit); James Blish's A Case of Conscience (ending not spoiled here, but it's famous, see the Wikipedia article).
UPDATE:
The Scifi Stack Exchange has been renamed to "Science Fiction & Fantasy". Both subjects are now explicitly welcome!
Shadowrun is futuristic fantasy. I would not be calling it SF. While it has some technological portions, it dwells too much on magic. That being said, I like it and I still have most of the shadowrun novels, yet have somehow managed to lose all my shadowrun rpg books in various moves.
Any sufficiently advanced technology is indistinguishable from magic
Some books make some futuristic things appear fantastical, such as in the Revelation Space, Culture Space and Darkness in the Deep series of books. Those are obviously SF. In the Shadowrun "universe", magic has explicitly returned. I think that's where I'll draw the line.
Wikipedia defines the fantasy genre as follows:
Fantasy is a genre of fiction that commonly uses magic and other supernatural phenomena as a primary plot element, theme, or setting. Many works within the genre take place in imaginary worlds where magic and magical creatures are common.
The Oxford Dictionary largely agrees with this description:
A genre of imaginative fiction involving magic and adventure, especially in a setting other than the real world.
Wikipedia defines the science fiction genre as follows:
Science fiction is a genre of fiction dealing with imaginative content such as futuristic settings, futuristic science and technology, space travel, time travel, faster than light travel, parallel universes and extraterrestrial life. It usually eschews the supernatural, and unlike the related genre of fantasy, its imaginary elements are largely plausible within the scientifically established context of the story.
And again, the Oxford Dictionary largely agrees:
Fiction based on imagined future scientific or technological advances and major social or environmental changes, frequently portraying space or time travel and life on other planets.
