I hate the word summary.
What everyone else refers to as a summary, I refer to as an attention getter. Because to me, a summary is summarizing the story. That's not what you want. You just want to get the readers' attention so that they'll read the story.
While I do think it needs to be short, I do think it needs a little detail about the story. Personally, I generally won't read stories when the description is vague (unless I know the author personally, so yes, I'll be reading yours, Julie, LOL), because when I'm looking for a fic to read, I'm usually trying to find a particular kind of fic. So if I can't see what the general plot is about, then I bypass it because there are a million others I can check out instead.