Having now used the site a little, I can see that there is a case to be made for a way to included rendered TeX. I would argue that:
- It has to be true TeX. Otherwise, we can't be sure that what we're seeing isn't some artifice of the method used to render it.
- It has to be explicitly selected for. Otherwise, it's confusing for newcomers to have their code suddenly converted.
- It has to be easy to separate from the Markdown markup. Otherwise, it gets confusing remembering what needs to be escaped and what not.
So here's a suggestion: a web-server that has a standard installation of TeXLive 2009 that can call tex, or one of its variants, on files uploaded. Somewhat similar to that done at the arXiv. But to encourage people to provide minimum working examples, there should be a quite low limit on file size. I would consider putting a limit on the number of pages rendered, perhaps 2 as sometimes issues are about differences between one page and another.
I would then have the server cache the result, either as a PNG (if small enough) and/or a PDF, and return a link to that cache, maybe using
md5sum or something to generate a unique URL that isn't too bad. This could then be included back in the question/answer using the usual Markdown image syntax.
As well as a file upload method, there could be a short-cut whereby the contents of a textbox gets processed inside some standard setup.