I think the second one is much clearer. How do various stackexchange sites decide on this and how does it get turned on?
How do you get it enabled? You
1. make a meta post suggesting that we add it (check!),
2. get community support for it,
3. one of the moderators makes a request to one of the Community Managers, and
4. they enable it.
Personally, I feel that there's a small number of questions that would benefit from it. Most of the time, there's an alternate way to explain a problem that is both easier to google and easier to understand.
However, the question you posted (and most ECDSA questions in general) would clearly benefit from being able to use MathJax, because there's already a body of literature about ECDSA. I see two good ways of going forward:
- Use one of the image-based workarounds to display math equations. The problem is that they're terrible. Once LaTeX has been rendered into an image, it's very difficult to edit. You can embed the source code of the LaTeX into an HTML comment, but then you're trying to keep two pieces of code in sync manually.
- Enable MathJax only on certain tags. (Is this possible/something the SE team will implement?)
We could, but the people at stack overflow don't want to unless it's really necessary, because it tends to slow down page loads a lot. I think most questions don't require the kind of complex math equations that would make having LaTeX installed nice.
This was discussed earlier here: Implementing LaTeX?