I once went to the town of Westward Ho! in Devon, which is a bleak and barren place: boarded-up amusement arcades behind a tempest-beaten promenade. However, it's the only place in Britain with an exclamation mark in the name. This is because the town was built from scratch in 1865 as a resort that would feed off the popularity of Charles Kingsley's novel Westward Ho!. The town was a marketing tie-in.
Kingsley's novel derived its name from the renaissance play Westward Ho! by Thomas Webster and John Dekker about a group of people who take a trip up the Thames to Brentford. The title came from the Thames boatmen who were going upstream who would shout "Westward Ho!"
So Westward Ho! being in the West of England is pretty much a coincidence.
There's also a town in Canada that is called Saint-Louis-du-Ha!-Ha!, but nobody seems to know why.
Exclamation marks are so rare in formal writing that many of the style guides simply ignore them like the drunk at a wedding reception. The Economist and Gowers' Plain Words fall into this camp (if you can fall into a camp) while The Times and The Guardian limit themselves to the three words: "nearly always unnecessary" and "do not use".
Fowler starts by arguing that !s must be used for exclamatory statements such as What a pity! or How dull! and wishes proper such as May the force be with you! This does not work for a normal reader. Alec Guinness did not speak with an exclamation mark in his voice and the main purpose of punctuation is to denote what voice the sentence should be read in. Indeed, this is not simply a purpose but an inevitable outcome of punctuation. Fowler vaguely concedes this point but then reels off a list of varied emotions and varied voices. To be fair to Fowler, punctuation and voice change more with fashion than most matters verbal, so I shall leave him be.
Instead, I shall go with Bryson who says that exclamation marks should be used to display "strong emotion or urgency" and nothing else. They mean that the voice should be raised. Eureka! The roadsigns that say STOP! are correct. The swooning women who cry "Oh God!" are correct. The Fun Facts columns that say "A cheetah can run at 75mph!" are wrong, unless you go around shouting at people about cheetahs, which I confess I sometimes do.
The crime against humanity, though, is the exclamation mark used to designate a joke. I took the main road out of town, but the police made me put it back!!! is a capital offence and if you ever do it I will hunt you down like a dog (I hunt dogs) and then do foul things to your corpse.
Worst, though, is an exclamation mark used to indicate a joke that isn't a joke. This is a variation of the person who exclaims, "I'm always losing my car keys,' and then laughs as though they had said something funny. Such people look at me hoping that I will laugh too, but I do not. I do not. I return their glance with a still, acidic gaze and reach for my set of recreational scalpels.
If this is replicated in print I get properly angry. I once received a wedding invitation that said that you could drive to the ceremony "if you can find a place to park!!!!!"
Five exclamation marks.
And then, when the church was set ablaze during the service with the doors locked from the outside, the police had the temerity to call my crime "motiveless".
Serves them right!!!!!