[martin-t]

It might be "proper" but I never liked it.

Many proper uses of the em-dash put two words visually together—despite being parts of two distinct units separated by the em-dash.

I much prefer using a normal dash with a space on each side - like this.

[lioeters]

Totally agree with this view. Why use an extra character when we already have a dash - just to add a pixel or two on either side. How an em-dash visually connects two words is not pleasant either, I prefer to have a space between them. For writing English, the ASCII character set is plenty.