I read recently that the colon and semi-colon is old fashioned and falling out of use and should be replaced by the dssh.
Such rubbish, whoever said that. I do hope you won't believe them, Maricellus!
. Why stop using a piece of punctuation that's extremely useful and precise? Precision matters in writing, or we lose the ability to make or words work on the reader as we want them to. Just because some people don't care to use them doesn't mean anyone else should stop.
The dash is useful, because it's vague. Sometimes that's what you want, especially when your writing is being inflected as much by how
things are said, as by the meaning of what
is being said. That's often the case in fiction and creative non-fiction, just as it is in relatively informal forms such as blogging
The dash is also disastrous, because it's vague: it doesn't express the connection between things, only that there's some sort of tiny pause. Colons and semi-colons express how the two things they join are connected: they're all about meaning.
There's a school of thought that you shouldn't use semi-colons in dialogue - and perhaps not colons either? I sort-of agree - at least, I see why it's said. In dialogue the sound-expressing function of punctuation gains in importance, and sometimes that should trump the meaning-expressing function.
But if you use dashes a lot - to represent different things - sounds - meanings - then the sense of what's being said soon begins to break down. That might be appropriate in any given bit of dialogue, if the speaker really is becoming a bit incoherent, or they're fumbling for what they're really trying to say. But it is something to be careful of. Less is more in this case.
Edited by EmmaD at 12:24:00 on 17 May 2014