This is not possible yet in q2a v1.5.4
I hope the gidgreen can implement it soon. Then it would be the tab "All user Comments" in the user profile, same for the questions now, example: http://www.question2answer.org/qa/user/VdoubleE/questions
http://www.question2answer.org/qa/user/VdoubleE/comments (not working yet)
For anonymous you can track their activities by using the /ip/ pages. Click on "anonymous" which is normally linked.
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