Why is called black friday?

As the holiday shopping frenzy kicked off this past 'black friday'. Why is it called 'black friday' anyway. Blame it on Philly.

Of course many refer to the fact that retailers are 'in the black'.

But the one I love attributes it to Laurence H. Black.

So which is it? The great thing about the Internet is you can find an answer, or answers, to just about anything; and since it is on the Internet it must be true, right?

But it makes it tough to get a straight answer when there are 120,000,000 search results on google. Maybe we should just make up another one to freak out the wikis.