I'm confused: I have just finished all the tutorials in the original EE, and the population cap seemed to work like you needed to build houses and town centers to raise the limit (like in EE2). But now I have started a random game, and suddenly my limit already seems to be at the maximum, 600 (1200 divided by me and my only opponent). I don't get it. This undermines the value of houses; are they worth only for the morale bonus, then? And why was it different in the tutorials?

OK, I obviously had gotten this wrong... Even in the tutorials, the second number indicates the total maximum of units to be produced, it does not increase with the construction of houses. What happens is that this number is much smaller there, something like 20 or 30, so I assumed that the town center gave some leeway to that. And I didn't pay enough attention to see that the houses did not affect this. :-P

Houses give all near buildings a buff to their health. I am not sure to how much or the curve for number of houses.

Yeah, I was just too used to the house mechanic in games like age of empires, and even EE2.