Responding to JD:

*I* think that the prospect of flooding the fellow's email box is unreasonable.

The original thread is a year old, and was dredged up by a reply post. Joe's lack of response legitimately may be because he no longer frequents the site.

A polite note of inquiry, sent to the author by an individual, would be a resonable way of trying to involve Joe in the current iteration of the conversation.

A flooding of his inbox would seem to flirt dangerously with the concept of a denial-of-service attack.

The reason for Joe's current absence from the thread may be nefariously negotiated or innocently normal. In either case, it is his business, and none of our own, as to whether he chimes in or remains mum.

IMHO