Furthermore, just because you don't have an address doesn't mean you can't receive mail! At least as recently as a few decades ago, there were rural communities in the US where nobody had a street address; the postal service knew where everybody lived and would deliver mail given just a name and town. I'm not sure whether this arrangement still exists in the US, but I'm pretty sure it still does in Ireland and probably elsewhere.
The push for 911 changed a lot of places by assigning street names, but the 911 folks are sometimes the only ones who know the names. UPS still delivers to some vague addresses on the reservation. Shipping to "House 311 behind the school" does tend to confuse a few Internet merchants.
When I was growing up in the 1960s, we just had a street name (which probably wasn't even required) and RFD #1 and the name of the adjacent town that handled rural delivery for the area. And this wasn't the back of beyond; it was just a couple miles outside one of the main Philadelphia suburban spokes. At some point they gave us a Box number to use although we didn't actually have a postal box and they continued to deliver in the usual manner at least until we moved around 1980.
In the US though, there was a real push to rationalize street addresses for emergency services in the late 90s or so. It may not be universal but I know of even summer camps at the end of dirt roads in Maine that have street addresses now.
