I once wrote in for clarification on the oversized passenger issue (not seeking compensation) and got 7,000 miles as a gesture of goodwill. Now that i know the policy I will not surrender any of my seat if they cannot reasonably fit in theirs.
Weather delays usually get me about $200 in compensation as an e-certificate, but that often depends on status and circumstance. Check out this thread
http://www.flyertalk.com/forum/unite...pensation.html to see what others have been given in compensation.