I received two similar emails yesterday, quite possibly relating to the same thread as some or all of the emails you received (the thread being from February 2015, and involving power cord wiring). The posts that were cited in the emails I received were certainly not objectionable in any way.
My guess is that the emails were automatically issued as a consequence of what I determined to be the fact that the entire thread had been deleted.
In any event, the emails do not appear to be phishing attempts, as the links they contain do in fact go to Audiogon. Also, the originating IP address that can be seen in the message "properties" does not appear to be suspicious.