According to the Jargon File, a journalist once asked hacker Paul Boutin what he thought the biggest problem in computing in the 1990s would be.
The Scarlet Letter | Dear John letter | White-letter Hairstreak | Letter-winged Kite | Letter of Majesty | National Letter of Intent | letter | National Association of Letter Carriers | Chi (letter) | Beta (letter) | Barons' Letter, 1301 | The Johns Hopkins News-Letter | Strawberry Letter 23 | My Letter to George | Moe Letter Blues | Loudermill letter | letter (message) | Letter from an Unknown Woman | Letter bomb | Hazing in Greek letter organizations | Habbush letter | Einstein–Szilárd letter | Delta (letter) | Dead Letter Circus | Chrysler 300 letter series | Canuck letter | American Letter Mail Company | Alpha (letter) | Zinoviev letter | Vav (letter) |
The reason for the common use of the three-letter acronym, בס"ד (BS"D), is probably because it does not contain the Hebrew letter Hei ('ה), that is used to imply the name of God, and for this reason, a page which contains the letters בס"ד (BS"D) without any other Torah content does not require Genizah (a process for writings that contain the name of God), and thus can be thrown away without a fear of desecration.