How do I find all comments by any given commenter?
Simply click on the name of that user or put their username into this web link:
For instance: http://www.tfmetalsreport.com/users/railroadbuff
Then you may click their "History" tab which will list all the threads in which they have posted.
You may also use the search box with in the upper right - trying entering their username as the search term.
Also, referencing previous post...