The 'Weird Sisters' figure prominently in Shakespeare's Macbeth. The play opens with a representation of a spell-casting session, in which the three hags brew a charm which will ostensibly lead the eponymous hero to his downfall. The witches themselves stand either for the inescapable force of fate ("poor Macbeth! He was trapped!"), or for the evil that his own corrupt soul has put into play ("evil Macbeth! Look what he has loosed upon the world!"), depending upon your point of view.
One last etymological note. "Weird" does not mean what you think it means in this context. Even though these ladies have beards (Act I, Scene iii, lines 45-47), they are not "weird" as we generally understand the term. While some have theorized that "weird" is a reduction from "wayward"--i.e. evil--the word actually comes from the Old English wyrd (Middle English werd) meaning "fate." These are, as Holinshed (who wrote the chronicles on which this play is based) put it, "goddesses of fate."
We hope that all readers of Waylaid understand instinctively that our three gentle ladies of Evanston, our Girls with Glasses, are no such cackling, grotesque trio of harridans. The resemblance is one of number, gender, and high-spirited entrepreneurial spirit. And nothing more.
So there.