I think that the post by
Coyo is an acceptable use of color - although I don't really see any benefit in the use of colour there, the text is already quite clear.
The other examples you give I find quite annoying - I can't see any reason why a big block of text needs to be coloured in this way. Maybe I'm getting old but I think good old Black and White is the best way of displaying info.
The only real use of colour that I can think of is to highlight a small section of text and even then
italic or
bold text is probably clearer.
Just my £0.02