I had been away from MSE for a month and a half, ending about last week. When I started looking at MSE again, the MathJax appeared unrendered on my screen, and when I answer a question, no separate box displaying my answer appears (although from the reactions of other readers, they can read the answers and see normally rendered MathJax.
I would guess that this was something done by my system (I am not the admin of my system) and that MathJax support was considered by the security or IT gurus to be "superfluous" except for one puzzling fact: When I go ointo MathOverflow, the MathJax works fine, my answers appear rendered as I go in the usual box, and in general everything is fine.
Does anybody know a clue about what might be going on with this? I thought it might have something to do with the experimental 6.2 release, which appeared in a Meta hot topic the day I started logging in again, but I think now that this is a coincidence, since I didn't do anything to get the new release.
Two more clues:
My questions don't appear in a separate box either, and this behavior goes for both MSE and MSE Meta.
And every time I submit a question or an answer I have to solve an easy captcha, which does not happen on MathOverflow. (Actually, I am not sure whether I am human any more, but I try to work under the assumption that I am...)