I don't remember that he does, either.  But he does (sort of) refer to the phenomenon.  Actually, I think all the examples he shows are human-made things (a car, a saltshaker). 

Yes, I think the idea is that there is "room" in the abstraction for the viewer to "enter". 

Well, pareidolia does not have be something completely random or naturally occurring. It can be any kind of stimulus that human beings perceive as significant, like seeing Jesus on a piece of toast or a howling wind that we interpret as screaming. It's pretty broad.

The "faces in places" internet meme - which is very similar to the electrical plug, pop can, etc. examples in "Understand Comics" - is definitely pareidolia. I do agree that visual abstractions like cartoons, avatars, puppets, etc. are probably different because they are deliberately designed to convey significance, but I also think it's closely related to pareidolia, which helps explain why puppets are so effective and why we respond to them.

Sounds good. 

"Pareidolia (/pærɨˈdoʊliə/ parr-i-doh-lee-ə) is a psychological phenomenon involving a vague and random stimulus (often an image or sound) being perceived as significant. "
http://en.m.wikipedia.org/wiki/Pareidolia
It doesn't have to be a face, it's about finding familiar shapes in random noise. I think it's most commonly faces because we're wired to look for faces as a way of connecting with our elders (as children). You might be interested in looking up the 'uncanny valley' phenomenon which discusses why we react to clowns, puppets, dolls and robots, the way we do. I haven't geard of Mccloud but from what you've posted it sounds more like a description of uncanny valley or suspension of disbelief than of pareidolia. With pareidolia you are imagining a face, for example, when one simply isn't there; what he describes is adding your own imagination to an already existing face.

Ronnie Burkett gave a talk once about how the audience, if sufficiently enraptured by the performance, will 'breathe with' the puppet giving it 'more life'. This film also talks about the suspension of disbelief and is worth watching if you can find a copy:
http://danhurlin.com/performance_work/current_work/puppet.html

The 'uncanny valley' phenomenon is interesting, too.  I've wondered if the fact that people respond variously to sociopaths could be read as having different personal 'valleys'.

I could go into length on that but don't think this is the best forum. I would state however that human behaviour in general is a bell curve and if you're at the fringes you are most likely to be ostracised for being different, but also have different ideas about what is acceptable. However, the uncanny valley is more about the way humans interact with things that aren't human but appear to have human qualities (ie AI in robots). The movie above touches on it in another way: we understand things to be either alive or dead; so we have an 'uncanny' reaction to non-alive things that have emotions, breathe, talk, etc. Someone in the movie likens it to playing god.

Start with your message. If you have a message you want to move your audience to action, then it is best to have medium that they can relate to and feel a kinship with.  Kids listen to puppets because they feel they are kids like them.  If you want to shock or broaden horizons then use a medium new to them.

Hi Zondervan. I'm making MY very first puppet also {the one in my profile pic}. I found a neat pattern source & am making their "glorified sock puppet". He's still a work in progress, but you can check him out in my album. His eyes are ping pong balls cut in half with the furry half of Velcro dots stuck on. I'm no sewing pro myself! But I sewed this by hand. I say just jump in, have fun, & learn from any mistakes you make, & use your corrections on the next puppet. OH! & here's the pattern source: http://www.projectpuppet.com/  Hope that was ok to give here by the way.

Wow that is a good first puppet, good eye focus and the tiny hat nice.  Those are great patterns.