Why are login fields mostly right-aligned?

Question

Most popular web-sites that require you to log in, have the authentication form on the right side of the page. More or less. As a right-handed person, I find it rather intuitive to look at and convenient to work with—that I don't have to sprain my neck or move my mouse too much to select the username field (though of late, most pages do that by default, immediately after loading completes). Not being omniscient I wonder how a left-handed person would react to the very same UI. Which begs the question: should this not be part of the web-site design goal to flip the forms for a left-handed person? Also, I guess it matters what language you are interacting in. For a language like English that reads left to right, having the form on your right probably makes more sense.

Some examples to look at with different layout of auth forms:

Facebook, Gmail, Y! Right
Buzzword Center
SOF Left

Feel free to share your $0.02. I'd also be interested to know if actual research has gone in to this.

Update:(02/20) Some excellent posts there. Good time to summarize:

The story so far:

• Most web-pages are static in terms of manoeuvrability.

• Users have little/no choice on how content is served.

• English being a the lingua franca of the Internet, web sites have, over time ended up using the left-to-right reading order of English as the order. This is in keeping with UI design guidelines.

• Being left-handed puts you at unease when using such web-sites (not a general rule perhaps, but people have experienced issues)

• Users tend to change habits rather than complain.

Clarification: Some of you seem to have misinterpreted my reference to mouse manoeuvre. It was supposed to serve as an example of what I think I'd take time to get adjusted to if things weren't the way they are. Cheers!

Answer 1

i'm left-handed. even more, i'm the only one i know that uses mouse on the left and swaps buttons (so the 'main' button is my index). but i don't see why you think that anything on screen should move 'for our benefit'.

one thing i've found by obsessively observing (i did my first semi-formal poll about this when i was 13 years old) other left-handed people's habits is that there's a lot more variety among us than among right-handed people. so, if you want to do some 'multi-handed' ergonomics, you shouldn't assume anything, just allow for maximum flexibility.