I don't know, but I'm excited too.   Being able to expand the boarders of the map mid-multiplayer game would be interesting.  I wonder exactly what would the trigger for it be.    I mean an area of attack?  why would a single area of attack open up the map?   Unless it was like a mountain pass or something, but couldn't a good wizard just fly over it?

At base, we know the world is going to work a lot like Civilizations.  You may not have borders the way Civilization does, but we may have 'range of spell influence' like in Age of Wongers.

If we were asked, I'd say give both sphere of influence(s) and national borders.  Though national borders may require a tech to be unlocked or something?

what really me are the things we haven't seen yet, like inns.  (your typo reminded me).   We know we have dungeons, and national borders might cause trouble for that (because it would lock out certain dungeon access unless you had open borders... then players would get pissed when you walked onto 'their land' to get a dungeon)

Also with shardes and such.   I mean, as much as I want to be able to say "My node!   you can't have it" by putting a national border around it, I really don't want national borders to exist just so they are more contested.  (in Civ, your boarders quickly are presseg against each other.  No space of neutral zone where you are not sure who owns what)

If 2 nations can lay claim to the same tile, then there is no point in having boarders.   because when I look at my screen I own everything I see, reguardless of what color they are.  So if there exist nodes, inns, random pots of gold, fires (I'm not sure why you get so much random stuff from camp fires in HoMM) or whatever, and I can see them... I claim them.  (unless somebody else beats me to there).  Having a national border would change this...   and having a national boarder that doesn't sync with what everybody else sees is useless

Scenario:

Player A:  Hey, you grabbed that stuff.  That was in my land!

Player B:  Nah, my screen says my territory extends this far

Player A:  But those bear cav units had to walk right past my city

Player B:   Yeah, my map says its mine

(the city is player A's capital... and player B lies)

Am I missing something, or have most of the replies so far mostly ducked the "persistent world" part of the OP's question? I'm also very curious about that idea, especially in terms of large/long games, but border questions are not the first thing that comes to mind when I wonder what that term might mean in a UI. And an expandable map seems almost the oppositie of a "persistent world;" it's a changing world by definition.

Well, given my lack of multiplayer experience, I probably have a weird first response to the phrase "persistent world," but what I *think* I know comes from Brad's very old journal on the subject and an even older one by Ilumino.

When I re-read those OPs, I notice more map-related stuff from Ilumino than from Brad, and both posts make me think that the major factors have to do with business of having "a game (map)" that users can enter, affect (play), leave, and then later return and possibly see evidence of what they did the last time they were "in the game."