Not a native Spanish speaker, but I don't think there's much to this. Signs and ads can be written in a formal or informal tone just as they can in English. On

Not a native Spanish speaker, but I don't think there's much to this. Signs and ads can be written in a formal or informal tone just as they can in English. On top of that, there's huge variation between Spanish speaking countries in terms of how 'tu', 'usted' and (sometimes) 'vos' are used, and Spanish speakers in Philadelphia presumably vary somewhat in their country of (ancestral) origin. Given all this, it's really not surprising that you find some variation. Ads that address people as 'tu' are common across the Spanish speaking world AFAIK.