Show if a user is currently answering your question?
3666
Show OPs if someone is answering, live
63393
How do you view vote history for a question or answer? or Add some sort of vote activity indicator?
94817
Allow me to save an answer
13367
Best way to deal with questions answered by the OP in the question instead of in an answer
610
Show all of my question/answers to me even if they are deleted
7611
How could I notify Stack Overflow's expert users about my new question?
118077
Provide indicator that another user is editing a post
39016
Inform new users if they can upvote an answer they accepted
48736
How can I find out if the current user is in a specific group?
25336
Give users a way to see their "Positive Question Record" score
91663
View question when answering
80261
notification for comments on Example Questions in Area51
123839
Let users editing a question know if editing it would add it to the reopen queue
147652
Get a notification when new answers are added to other people's question
102221
Color of questions with accepted answers on user profile page
30528
Requesting an active user page
140926
Can I re-ask a question if it hasn't been answered?