Em dashes — your thoughts?

Hmmm. Are not there three? 1) dash, 2) en dash 3) em dash? Which requires fewer keystrokes to enter? Dash, I think. The others are cuter, but I will go with dash.  I have used computers since 1980. That is a lot of keystrokes. Must keep them to a minimum.

Another wide-spread though very particular use of the em-dash is in legal documents, to fill the gaps of empty space with. This mildly prevents any fraudulent action, like adding words or figures after numbers to a line of text. In the sample below, a typewriter has been used, so the only available dash is a monospaced one. But in more sophisticated documents, an em-dash might be used.

Another use I've heard of (but for which I can't find any proof), is the em-dash as an ancient way to mark a new sentence. When paper was scarce, scribes just kept writing lines of text across the whole width of a page, without breaking it up into paragraphs. That's what the pilcrow character was intended for. And in a similar fashion, in stead of using a period, scribes used a longer line (like the em-dash) as a weaker break than the pilcrow, to clearly separate sentences from each other.

In Russia, we have quite strict rules of using Em Dash:
- Starting dialogues
- Connecting Direct Sppech with the rest part of the sentece

- Connecting Subject and Predicate in the sentence if they are nouns or pronouns.

Other using may exist as an "author's punctuation", but not very often, mainly for increasing the pause after some complex parts of the sentence (e.g. long list in parenthesises, several levels of nested sub-sentences etc.) Too many Em-Dashes (as well as too me=any emphasises) is concidered as a sign of low-skilled author with some mess in the head

Other dashes have their own job. But, certainly, some authors and typeseters use punctuation at random, so we check it on every project.

We use Em Dash with thin spaces around.

It must be Friday...

I'll use whatever convention is the house style or editor's choice. When this is communicated, I could not care less. Whether en or em dashes, it all pays the same.

When it's up to me, I'll use em dashes. Why? Because that is the (general) convention used here in the US. And I am never against editing the font to make the dashes "proper," whether by decreasing their widths and/or increasing their side bearings. Even a lot of Adobe get it wrong.

Take for instance Adobe Garamond Pro. The "M" has an advanced width of 912 units (Font Units). But the M character itself has 879 units at its widest parts and has 22/33 units of side bearing (L/R respectively). The Em Dash has an advanced width of 1000 units with zero-width side bearings. Which is far wider than the actual convention wisdom of the em dash being equal to the M bounding box (which is the advance width).

How I make my fonts is also not conventional in that I make the, in this case, em dash generally equal to the width of the M where the em dash aligns across the M character. So with Adobe Garamond Pro, I would have made the em dash's advance width equal to the M's at 912, and the em dash's width 654 units and off set to the left from center.

First screen shot is using the original em dash, second is of the modified version

In German the M-Dash (Geviertstich) is rarely use, it was used as Streckenstrich to symbolize the way between two cities, like Wien—München, but more and More then N-Dash has replaced the M-Dash.
The N-Dash has several positions or meanings:
– as bullet
– as Gedankenstrich, used like in the US the M-Dash in its meaning, but with typographic differences: it musst be used between a normal space and another space, a comma after the dash is allowed and it should never be at the start of a new line.

– as new Streckenstrich in replacement of the M-Dash.

– as Bis-Strich between numbers or ranges of numbers, like Bible Vers references: Psalm 25,15–18 or range of time, mostly in tabular form.

Looking at it from an aesthetic standpoint, i.m.h.o. the fabric of a text gets too much disturbed by these super long em dashes. And by using spaces narrower than a regular space, the surrounding word shapes also tend to distort a tad, decreasing its legibility. (That's why I also use a regular space between a word and punctuations like question and exclamation marks, like in French.)

Look at the one on the right, the phrase or term almost looks like an inline heading !

So whatever the regional trend is, my personal approach is to use n-dashes and regular spaces. That seems to me the best option to make such a phrase or term stand apart enough and slightly disrupt the train of thought while reading.

I’m—a—huge—fan

In the US (you/they) tend to use em dashes – in the UK (I/we) tend to use en dashes with a thin space either side of it.