Well, looking at my code I see that

$noLineCode        += scalar(grep { $_ =~ /\w/ } @aLine);
[download]

will include POD as well, so... it actually measures "code" as opposed to "whitespace", not "code" as opposed to "non-code". Eh, so to speak :)

It depends on what you want to measure and what you think the metric says about the source.

/J