I've now added my article, found here:
http://www.schoolofpuppetry.com.au/tutorials.php/how-to-make-a-foam-puppet-aamp-what-kinds-of-foam-to-use

Thanks again Andrew for the help!

I purchased foam from a couple suppliers for years. One closed, the other quit selling the foam I used. 
I've been to two different foam places to purchase foam, and they asked what density I wanted.  I really had no clue.  One place, the guy said he would suggest a sheet of their cheapest foam, and if that did not work we could do something else (it was not what I needed). The other place sold me rolls of narrow pieces that they had cut from larger rolls.  This worked well, as I could experiment with several densities and decide what was best.  Now I will take a piece of the one I liked the best and they will sell me larger pieces.  I have no clue which density this is, but they said they can tell by looking at it.    Said all that to say... perhaps we should be listing densities to help folks getting started. 

Sorry Na but I have to disagree on your section entitled Common myth: polystyrene or "styrofoam".  I think the thing that triggered me on this the most was the line "Anyone who writes this hasn’t spent a lot of time using or making puppets.". Ahh... I would use it and have used it.  Remember that just like the poly foam that is used to make the common hand in mouth puppet, there are a large variety of grades and types of polystyrene foams. We are all more comfortable with different mediums and I feel you should take that into account. Do not dismiss someones work simply because of the medium they have chosen to work in.

P.S.
It is a great article overall.    I didn't want you to think I didn't appreciate it.

Actually, I kind of agree with you. Initially I had written it up in terms of "styrofoam" because that's the most common term used in hobby tutorials on puppets for kids. Then when I realised that floral styrofoam was used by Fratello, I rewrote it.

The problem I have is that 99% of the free tutorials out there do recommend using things like polystyrene cups for making muppet heads. While I think polystyrene is perfectly fine to use for certain puppets, the aim of the article is mainly towards those making muppet-type puppets and in this case recommending people away from polystyrene is probably a good idea.

Maybe another rewrite of that section is necessary, with some clarification in regards to what I just said here.  EDITED TO ADD: I've made a footnote explaining my reasons at the bottom of the article, along with removing a few small sentences from the actual paragraph in question.

I'm certainly not dismissing other people's choice of materials, but you've got to remember my readership is mainly non-puppeteers who want professional results without having to wade through nuance to get it. I do actually say at the beginning of every article on materials that you can use whatever you want, but some things might be better for your needs.

Plus, I have used polystyrene before and had it break down on me when trying to use it.

Feel free to criticise, I enjoy discussing this stuff, and am more than happy to make changes where I'm wrong.

I purchased foam from a couple suppliers for years. One closed, the other quit selling the foam I used. 
I've been to two different foam places to purchase foam, and they asked what density I wanted.  I really had no clue.  One place, the guy said he would suggest a sheet of their cheapest foam, and if that did not work we could do something else (it was not what I needed). The other place sold me rolls of narrow pieces that they had cut from larger rolls.  This worked well, as I could experiment with several densities and decide what was best.  Now I will take a piece of the one I liked the best and they will sell me larger pieces.  I have no clue which density this is, but they said they can tell by looking at it.    Said all that to say... perhaps we should be listing densities to help folks getting started. 

Forgot to say this is a good idea: what densities are commonly used?

Most foam companies will send you sample pieces of all there foams so you can compare the densities, the ppi or pores per square inch. Albany foam was nice enough to send me big 12" X 12" x 4" squares of all there foam they have in stock. It made a big difference to be able to hold the foam blocks in my hand. I agree that this is a great to know when making foam selections. You can look in the Albany catalog to compare densities. I'm not sure I understand it all......... densities,ppi,foam compression. Some foams can have the same density one soft and one firm. I'm a hands on person.

http://albanyfoam.com/

Na,
You had asked about using polyfoam for other types of puppetry.  I had remembered this but just found the images in the Gallery that show how Abdolos uses block polyfoam to sculpt his head and body on marionettes.

http://puppetsandstuff.com/community/index.php?action=gallery&g2_itemId=16404