In reply to Peter Knight (@peterrknight).

Agree 100%.

I was more making the point that, in designing for mobile audiences, one should not neglect the desktop audience which is still by and large the majority of visitors. Mobile first or desktop first should be a matter of workflow preference, since the end result should be both an optimal mobile experience and an optimal desktop experience. This is something that I think the "mobile first" mantra doesn't address by itself.