Double-spacing

There was an essay at Slate ranting that two spaces after a period is no longer necessary and just wrong.  As if.  It is left over from the age of manual typewriters, when all characters took the same space, yada yada yada.  He even notes that it's a convention, but it bugs him no end that it's an outmoded convention.  He pays attention to which of his friends persist in this solecism.  No, I'm not linking to it.

If my double-spacing after a period marks me as someone who was properly educated in the age of manual typewriters and paid some attention, I'm regarding that as a feature, not a bug.