Multi-threaded Verification MtV - taxonomy challenge

This evening I was speaking to a friend of mine on how to effectively utilize the 2-box, 4-core each machines he has at work for functional verification. He is exploring to add additional simulator licenses (did I forget which vendor :-) ) and was curious if he needs to add more machines or can he better utilize the existing ones.

During the discussion it became apparent that we have differences in various terms and their meanings. After the phone call I was casually browing edn.com and found a seemingly relevant article:

http://www.edn.com/article/CA6662624.html?industryid=47037

But a quick read didn't look like what I initially thought it would address. IMHO, while Multi-threaded Verification (MtV) is becoming mainstream (albiet slowly), it is a good time to agree upon the taxonomy for this new paradigm.

More on this later..