I noticed that I nearly never use landscape mode except when I have to (apps with fixed orientation) or when watching videos. But of course I don't want to consult customers based on my own behavior. So does anybody know if there is any data on usage of landscape mode on smartphones or tablets?
Less an answer and more a word of caution:
Be careful not to let your personal experience and preference cloud your judgment for what's best for the actual users of your products and devices. Which orientation helps them get shit done? Prefer that.
I find it a little concerning that the first few answers are all: "I like portrait better. I like landscape better. I like switching between them frequently."
Isn't this how the never-ending control preference holy wars start?
Dev: I hate it when lists are organized into dropdowns. They're jank, man.
Design: What are you talking about? It's such a compact control and familiar! Everyone knows how to use it.
Mrkt: Hmmm. We should only use dropdowns if we can brand them. How long will that take?
Mgmt: I've decided. No dropdowns. We'll use a long list of radio buttons because my grandma and I like how they look like plastic bubble wrap.
Be orientation agnostic.
I know people who use their iPad to communicate because of speech issues. They always use it in landscape, often with large fonts so they can turn it to show. I asked one specifically on Twitter and she almost never uses it in portrait. Apparently it's harder to use the gestures for her at that angle.
So it depends on your audience. Are you considering people with disabilities who may use the iPad differently from a general user and of course there's personal preference.
Best thing is to let the user use whatever orientation they want and plan for both to be used with equal ease. Then do user testing to improve.
I find I alternate between both, so fall nicely in-between both you (Phil, Mike).
Although I probably default to landscape more often than not certain activities are more comfortable portrait, such reading or using particular apps e.g. Twitter.
I'd be surprised if there had been any significant research carried out already but its probably only a matter of time before some results are released. I't might be worth putting a basic poll/survey together and seeing what the consensus of opinion is rather than inviting discussion here. I'd also be interested to hear the outcome.
Depending on app I will use my iPad differently. More commonly though it is dependant on where I am. If im on the train, buss, airplane etc. I tend to use it portrait mode since the elbow room is limited due to other passangers. If I need to use it simply sitting on a chair I prefer to keep it in my lap in landscape mode since I fear I will drop it between my legs if I use if in portrait mode.
My point is that the functionality of the app is not the only thing that matters but also the current environment and ergonomics possibililties of the user.