(I'm >>30)
>>31
I can't argue with the fact that this is a fancy name for a very, very simple technique.
>>33
If you express the requirements as unit tests (which is a good practice IMHO), you don't go past the method level, do you ? (i.e. the finest thing you can control is see if a method's effects fits the requirements).
The PPP is basically writing a summary of what your method/routine will do, then write your code after the corresponding comment. Typically you'll get 1-10 lines of code per line of comment, sometimes more if the code is straightforward.
It goes more in-depth than what you would achieve by unit-testing (since it explains the inside of a method), and arguably it may be overkill, but if it's decided on your project that there is a need to comment, it has good points :
_ it ensures comments will be written
_ it ensures only useful comments are written, too - too often have I seen worthless comments such as "// increment i by one" - with the PPP, since you write a summary, if the code is simple you won't write much or at all
_ it is much less boring than writing the comments afterwards - going back and commenting all the code you wrote during the last 10 days is dull, dull, dull