But it is.
Your bio - which will appear in program guides, anthologies, and after magazine articles, should convey both the tone of who you are and give a sense of what you've done... but in a very, very brief space.
I recommend having a pre-made bio that fits into a thirty word length, a fifty word length, and a hundred word length. Those are the most common lengths that I see editors ask for - and having them pre-written means that you'll be able to quickly snap them off when needed.
Also: It's tempting to list off all your publications. Don't bother. That is what your web page is for. (Exceptions for people who have won major awards like Hugos, Nebulas, and the like, of course.) When I have extended room in my bio, I tend to list the works that other people have written that I have published... but that's a situation you probably aren't in.
So for example, my thirty and fifty word variants:
Steven Saus's work has appeared in anthologies and magazines both online and off. He publishes and provides publishing services as Alliteration Ink. You can find him at stevensaus.com and alliterationink.com.
Steven Saus injects people with radioactivity as his day job, but only to serve the forces of good. His work has appeared in anthologies and magazines both online and off. He also publishes and provides publishing services as Alliteration Ink. You can find him at stevensaus.com and alliterationink.com.
Note that the second one sets the tone - humorous, but slightly sinister - that pretty much fits most of my work. It's also very memorable - I have people quote it to me at conventions. Also note that I leave out http:// - folks know to put that there, and modern web browsers will automatically add it as well.
What do you think? Are your bios longer? Shorter? Share yours in the comments!