This is one of the most basic bits of knowledge about the game, short of "You control dwarves in Fortress mode".
Wow, that's a little bit of an overstatement. I think it would actually be pretty easy to not know this, as you don't have to go anywhere near other settlements in adventurer mode and I hardly see anything about it anymore on the forums. And those other two points, but I never come across it on the wiki and, well, I guess you're right on the fourth one.
well the wiki got revamp for 34 and kinda dump all info on 31. somewhere.
but 31.xx wiki does state adventure mode dwarven homes don't exist.
Other Sites
Note: As of version [31].25, only humans have civilization sites.
Elves live out in the forest, literally. Although defined to specific regions on the map, they have no structural wealth whatsoever. Some trees are named.
Dwarves live underground. Their entrances are large square pits with stairs around the perimeter, and a row of leading down into the fortress halls at the bottom. The main halls are wide and have pillars near the walls, long and occasionally turn corners. Different levels in the fortress are marked by a row of ramps with two pillars on the side (walk towards the side of the ramp that has the pillars) and, although the number of floors in a fortress can vary, they are usually little and only become deep if the lay of the land above is variable. There are two-tile-wide hallways, empty 5x5 rooms, and scant Dwarves in these pre-fab fortresses. It's obvious the computer is playing a completely different game than you are in Fortress mode!
Goblins live in obsidian towers, usually found built in twos, though they both don't necessarily have to be built up. One could be a "tower," one could be an over-glorified "basement." There is probably a temple nearby, completely similar to human temples. Goblin towers have tight 1-wide hallways, spacious and empty rooms, and strange hall extensions that end in remote cross-like dead-ends. Like dwarf fortresses, there is rarely anything in a Goblin tower asides from Goblins, and they have a strange tendency not to attack non-Goblin visitors. They seem to have lots of children.
You may come across what the map defines as a "Goblin" city that is actually populated by Humans or Dwarves living in or around the towers.
okay this kinda doesn't say word by word that dwarven homes don't exist but it's noted that only humans kinda exist. also the part about never been on the forums before kinda leads to either
A. the person search by search function
B. the person search by paging through manually looking for a thread on the subject.
C. didn't search at all look at the front page.
I think 1. means they never played 31.xx which unless you modded or gen a world where dwarves fought humans which lead to them taking over a human settlement.
But yeah overstatement.