But why are the titles different sizes? There may be no reason beyond aesthetics, but that's his point: differing sizes often conveys information, and even if it does not, it takes effort on our part to realize that size differences does not imply functionality difference.
And if I did see a double-door immediately next to a normal sized door, I would wonder why that was set up like that. Is one the emergency exit? Is one the freight-entrance?
Tiles are different sizes depending on their intended use. App tiles on Win8 are active - i.e. the app can render new information to them. A newsreader app can tell you most recent headlines at a glance (without having to launch the app), your email app can tell you number of unread messages, weather can display current conditions without forcing you to launch.
Larger tiles are used by apps that need to convey more information - your email app that just shows an unread count probably doesn't need more than the standard 1x1 tile, your newsreader might want a 2x1 to have room for headlines.
I'm not a huge fan of Metro, though I have been actively devving for Win8 for a few weeks. I don't think this is really a problem - all of this stuff is pretty obvious to users.
My experience has been that "Windows 8 Apps" default to the 2x1 tile size and all "pre-Windows 8 Apps" default to the 1x1 tile size that displays their "desktop icon".
So the rule could be: "All apps start at 2x1 if they have a 2x1 tile designed, otherwise they start at 1x1"
You're being glib, but the main entrance to my building has a revolving door in the middle, and double doors on either side of it. The preference for us is to use the revolving door because it's more energy efficient. So, yes, there are situations like this in the wild, and there usually is a "why" behind it.
There is a "why": the tiles are different sizes because I made them that way, based on how I use my phone. The tile sizes in WP8 are user-customizable. Examples from my phone:
- My email tiles are the smallest (1x) size because they still show unseen count at that size (also shown on the lock screen), which is the only "live" information I care about for them. At 4x they will show the name of the email account (which I don't need, since I can tell by the icon) and at 8x they show the subject line of the most recently received email, which I don't personally care for.
- Same goes for my phone and messaging tiles, as well as IE and maps, which have no live functionality
- I use a 4x tile for my calendar for two reasons: 1) I've put it in the top corner of the screen, and 4x makes it easier to reach if I want to open the calendar app, and 2) at 4x it shows the day, date and next calendar appointment (also shown on the lock screen, but I like it here as well).
- The pinned-contact tile for my wife is 4x because the vast majority of communication I do on the phone is with her, and because I like seeing her picture there. Plus, at 4x, it shows Facebook status updates and sometimes other stuff.
- I keep the Weather Channel tile at 4x because it shows today's forecast.
- Pinned websites are all 1x, because they don't update and I can tell from even small icons what they are.
- A few other apps that I use (I personally don't use a lot of apps except the stock ones) are pinned at 1x, since they don't have any live functionality I really care for.
I've always thought the "live tile" idea was a bit oversold since in the majority of cases I don't really find it useful (I don't really count things like email unseen counts as live tiles - even if WP8 didn't have live tiles I would still expect that information to be there, like it is in iOS), but the new WP8 ads about being able to really make it "your" phone definitely ring true. If I had other apps, workflows or priorities it would look completely different.
And if I did see a double-door immediately next to a normal sized door, I would wonder why that was set up like that.
Because more people or larger objects use the double door. In both cases, it has nothing to do with you as user using the door, so you're wasting brain cycles thinking about it. It's a door. Walk through it.
it takes effort on our part to realize that size differences does not imply functionality difference.
No it doesn't. Size may imply significance difference (which is the "why" you're looking for) but I can't think of many cases where it implies functionality difference. A double door serves the same purpose as a single one.
Trying to figure out if there is significance in the door sizes is not a conscious thing - and it is important to do this sort of thing in the background, unless you want to be to be the one who trips the fire alarm.
But fire doors are the size of normal doors. They just tend to have giant warning signs on them, are sometimes painted red and tend to have "push bars" instead of handles.
Door size has very little to do with fire door "affordance".
...and in your example, you said a normal sized door next to double-doors. Yes, there are other signals indicating emergency exits. But I was assuming, from your example, that the only piece of information we had was the door size. My point was that most people would then look for other signals to indicate what was going on - such as giant warning signs and push-bars.
And if I did see a double-door immediately next to a normal sized door, I would wonder why that was set up like that. Is one the emergency exit? Is one the freight-entrance?