Formatting Web Pages for Printing

I’ve been wondering for a while about the correct way that web pages should be formatted for printing:

In my view they should be WYSISWYG.

Otherwise you get the situation demonstrated on this page from the BBC’s webpage – that by pressing print you lose the interesting diagram:

And I also seem to see an increasing amount of paper wasting non formatting: as demonstrated by this page:

So the question is: How should web pages be formatted for printing ?