Popular?

Australia's most popular barista made coffee. Hmmm.
Who determines the meaning of the world "popular"? Because I would have bet - contrary to what their sign would have me believe - that the most popular barista-made coffee in Australia does not come from Maccas! And if Maccas, or a disinterested third party, had conducted a survey would they have put the names of other popular coffee franchises on the list? And if they did, would it have been representative given that most coffee chains are not Australia-wide and even food franchises that are nationally available rarely have a dedicated cafe area? So ... what is their definition of "popular" and how representative was their research?