Wood blocks underneath components?? snake oil?

No snake oil at all, great for resonance control and added dampening. Very inexpensive DIY techniques, I would even go 1 step further and try Frank Tchang's feet, beautifully designed stacked and insulated wood feet with holes drilled throught the structure, really tunes your sound.

If you go on to the Cardas.com website to read about the Cardas Myrtlewood Golden Cuboids, the basis for this product introduction is explained. It is hidden in the "accesories" section.
Ayre has these labelled for them, I believe.
Basically, vibration absorbing, and an apparent tuning effect, combine to improve performance. Works well where I have placed them, but no single brand of reasonably priced footer is "perfect" for every component, so you have to listen when trying the myriad of footer choices out there.
The Cardas Myrtlewood Golden Cuboids (the rather Biblical sounding name kind of gets you in the mood to hear better performance, don't you think?) are inexpensive, don't add any instability to the supported component, and do not add much height, compared to the original equipment feet.
There are now very many support products competing to create the best support for a given item. If you never try any variations in component support, then you may never "miss" them, but fascinating to hear differences, if that is a part of the audio hobby you might enjoy.

The idea is that different kinds of wood have different energy absorption properties. So unless you live in a cave and hang upside down maybe just maybe you will hear a difference in sound change. I would just get a very good rack or an attractive piece of heavy furniture to your liking and enjoy the music.

For an explanation go to: http://www.stereotimes.com/

the "Archives" section and the article "The Art and Science of Audio System Tuning, Part 4."

I've experimented with their recommendations, and found that wood blocks make changes in your system and those changes vary with the type of wood used. I've even measured the differences with my SPL meter using a test record and different frequencies yield higher or lower Db levels depanding on the type of wood. But you don;t need a meeter because the differences are clearly audible. I found zebrawood to be my favorite and is now under all of my equipment - I wouldn't be without them. I did find an even greater improvement with something like a Vibrapod placed between the wood block and the equipment shelf - equipment on top of wood block on top of soft absorber on top of shelf. V-Pads - rubber/cork absorbers - make a good cushion under the wood block (or under anything, for that matter)- V-pads are cheap @$2. and available heating/airconditioning suppliers.

But you don't need to spend a lot to experiment with wood. Simply go to a local hardwood retailer and buy 1-2' of a few types of wood, cut them into 1"x1"x2" or larger blocks; at lease one dimension should be longer than the length of your equipment feet so that the block can be placed directly in contact with the equipment chassis completely avoiding the equipment feet. And, it seems best not to set the equipment in end grain.

Give it a try. You'll be amazed what changes such a simple and cheap tweak can bring. Depending on your system and the type of wood you use the change can be very positive. Have fun!

p.s. If you can't find any hardwood, let me know and I'll send you some of my extra blocks at no cost.

It will sound woody if you believe.