Instead of worrying about 50 shades of grey for label and placeholder text, Jared asked "Why have both placeholders and labels"?
IMHO:
* A label identifies what a field is for, even after text is placed inside of it. * A placeholder gives an example of field content.
These are somewhat opposed. A further way of looking at it is to imagine a long form fully filled out -- how do you verify, as a user, if you've filled it out correctly if the labels are no longer visible (because you've filled in the field).
On mobile, for short well known forms: e.g. password forms; there might be an argument. But I would certainly rather not see this as the default.
~Matt Walker Wikimedia Foundation Fundraising Technology Team