Cell phone vs. PDA's an Laptops for secret communication?

  Why are text messages better?
  
  CD quality sound ~ 10 Meg/minute.                16 bit, 44.1 khz, stereo
  phone quality sound ~ 750 kilobytes/minute       8 bit, 11 khz, mono 

  Let's estimate 60 words/minute
  
  Text ~ 60 words of text will take much less than 1 kilobyte.
     ASCII - each character = 1 byte

Encryption on the web-

Hidden page
   no links to it
   not registered in search engines.

 An example of hidden messages on the public web.

The password is "go".

Expand on this concept-
  Using slightly different color shades to represent binay data?