Why women's clothing sizes are meaningless

Now this is an article any woman should identify with.  Why when you go clothes shopping are the sizes so wrong?  Or are they right?  A size 10 in one store might be an 8 or a 12 in another store.  Why are pant lengths so long?  If petit means clothes for shorter, thinner women, how about the stouter, short woman.  Sizes and lengths make no sense.  

Lots of good information in the story, especially the history of how women's sizing came to be and what standards were used.  But for today's shopper it basically boils down to this:

Vanity Sizing. Women don't want to know their real size, so manufacturers re-label bigger sizes with smaller numbers.