Microsoft recently introduced typing via Windows key plus hyphen (en dash) and plus shift (em dash). Much easier.
replyI think offsetting the em dash with spaces is contrary to almost every style guide.
replyI think this is a localisation issue; in the UK, it's much more common to see space-surrounded em dashes.
replyChicago does it one way and AP does it the other.
replyI definitely prefer it un-spaced, though, personally.