"Al's Furniture Store" isn't advertising to me, it's the store name. I decided to go look inside based on what it was.

If 'Al' wasn't able to put his business name on the building (or advertise in any form), then he'd probably not make very many sales.

It surprises me where the conversation has gone -- this being HN and all, we're mostly startup/biz/tech people round these parts.

I intuitively understand what you're getting at, but I think it's difficult to draw a legal line between a name sign and advertising.

I guess plain signs reading "bakery", "clothes", "cars", "hipster coffee", etc. could be allowed if you try this.