Hidden Wizard, Steelcurt--
You just made some good points.
However, those of us that are using newer s/w don't have a problem. For instance, my iPhoto, Lightroom, Photoshop apps, and even Apple Mail recognize the EXIF information the iPhone presents in its photos and renders accordingly, that is, portrait is correct and landscapes are right side up regardless of camera orientation. The raw photo is of course presented as taken, which is the way I think it should work (but who cares what I think, right).
Again, older s/w, and apparently Outlook, do not handle the rendering correctly according to the EXIF standards. Until these applications catch up, if I'm planning on sending a photo to people I know on Windows platforms, or my mother-in-law who has a 7 year old iMac, I make sure I do one of two things:
1) Take the photo in landscape with volume buttons down if I'm going to send directly from the iPhone. Again, I submit that the majority of users were doing this because the screen shutter bottom is on the right. Also, I don't do portrait orientation if I'm sending to these same people.
2) Process the photo with a third party app, or iPhoto, then send. This is presuming I took the photo with other orientations with the iPhone. There are a lot of photo apps that can do this right on the iPhone, so you don't necessarily need to go to a desktop to do this.
Note that this whole issue is a non-issue for people with newer Mac systems.