This is just out of curiosity. I am seeing live data getting pushed and updated on Stack Overflow question pages.
- While I am seeing an answer posted, if the author is updating his answer or the question is modified, I see messages like - 'this answer is changed / updated, click to load'.
- The time keeps updating without a page refresh, minutes keeps increasing showing the time since the answer or question was posted.
I understand there are tools like Node.js and other server push technologies which makes this possible, but I am just thinking: What is Stack Overflow actually using and how are they doing this?