1) Answered questions have a green checkmark by the answers count.
2) All comments attached to the question are ordered chronologically, with the earliest answers first.
3) Comments accepted as an answer by the questioner are rendered with a dark green background.
4) Comments by the questioner have a light green/grey bar off to their left.
Example of 3) : http://ask.metafilter.com/261436/Should-my-math-student-have...
Example of 4) : http://ask.metafilter.com/261436/Should-my-math-student-have...
HTH. :)