Sony SACD mysteries

I'm interested in SACD technology. But I'm puzzled by this:

http://interprod5.imgusa.com/son-637/technology.asp

"Unfortunately, the PCM process exposes the music to a "decimation"
filter during recording and an "interpolation" filter during playback.
These two filters can smear the sound, corrupt the sense of space
around the instruments and sacrifice the subtleties of live music."

- What do the quotation marks signify?

- "Decimation" means "killing every tenth man", according to my
dictionary. What's that all about?

- I think I understand "Interpolation" which is about filling in
a missing value with a guessed value. Isn't that more to do
with error handling?

Or this:

"The Direct Stream DigitalT pulse train "looks" remarkably
like the analog waveform it represents. More pulses point
up as the wave goes positive and down as the wave goes negative."

- How do I "look" at a pulse train?

- What are the benefits of this "look" to the audible results?

Or is this mumbo-jumbo to impress those who do not understand
it? Having said which, I don't understand it, but I'm not impressed
either.

Tim