In every page title on tex.sx, it says
TeX - LaTeX - Stack Exchange
These horizontal lines between the words are hyphens (Unicode point U+002D "Hyphen-minus"). In proper typesetting, these should be dashes, either En Dashes (U+02013) "–" or Em Dashes (U+02014) "—". As I would say we're a community who cares about such details and who thus ought to be a role model for them, I'd appreciate to see that changed.
The difference between these three characters is directly reflected in (La)TeX by three distinct inputs,
-- (En Dash), and
--- (Em Dash). A similar issue has been discussed at New user greeting., which now uses an Em Dash:
Welcome to Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems — check out the FAQ!
I'm not a big fan of the Em Dash, I think it interrupts text flow too strongly; nonetheless we should use dashes uniformly. Has anybody seen any other proper dashes around that would have to be adapted similarly? There are more pseudo-dashes (= Hyphen-Minuses) around here, e.g. after the title of a page, be it a question, "Frequently Asked Questions" or a user page:
Putting a bar in the margin - TeX - LaTeX - Stack Exchange
So if you were asking me, I'd say we should use En Dashes on all occurrences of a dash (except one), with a regular space before and after it. Exception: It might make sense to use an Em Dash between a page title and the site title and En Dashes in the page title, like
Putting a bar in the margin — [= Em Dash] TeX – [= En Dash] LaTeX – [=En Dash] Stack Exchange
This would reflect that there's a bigger "content break" between the first part and the rest than there is between the TeX, LaTeX, and Stack Exchange, but I don't know if that is a typographic no-no according to the one or the other typography bible.
Related questions (this will help with keeping everything consistent and preventing misinformation):