Slashdot's page is pretty inconsistent when it comes to
dashes. Readers and editors use a mix of m-dashes,
single hyphens, and double hyphens, with or without
space on either side, where an m-dash would probably go
in a print publication.
I suggest automatically (on submission) or on command
(in the backend, as with fixquotes) replacing every
instance of (two hyphens with a space on either side)
with a single m-dash with a space on either side.