There is much confusion. What I was referring to in the post above is that when I bought my first 29er, several friends honestly thought the diameter was bigger than a 700c rim. When I told them that my vintage 27" rims were in fact larger (630 versus 622) than 29er rims they thought I was nuts.
As you know, marketing hype is such that 29er is much sexier than saying "rim accepts huge tires".
I have a dirt jumper with micro knobby tires on it. The rims are conventional 26" mtb, but the tires make them look much larger. I believe they are 2.25", but look massive.
The latest thing is to call something a "cross" whatever, bike, tire, frame, rim. Just like adding "touring" in front of an old beater is supposed to help sell it I guess.
Getting off-topic, but how many products use the word titanium in their marketing. Golf balls even. Way overused and overhyped.