{HEAD ~ a thread level} representing a response level of each of the at least two e mail messages within {TAIL ~ the mail thread} and inserted into a thread level field; and 
{ HEAD ~ a thread level } representing a response level of each of the at least two e mail messages within { TAIL ~ the mail thread } and inserted into a thread level field ; and
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH