The Law of Proximity
In design, the Law of Proximity states that objects that are near, or proximate to each other, tend to be related. Users inherently expect things that are related in theme or function to be grouped together in space. When this expectation is violated, confusion and/or frustration results. This is a classic example of bad user experience.
In this case, I spent a mere ten seconds updating my Twitter profile blurb...then spent way too much time trying to find the control that would allow me to commit the change. Couldn't find it, couldn't find it, couldn't find it...oh, wait. It's on the opposite side of the page, nowhere near the part of the page I was working on.
Don't do this to your users. It makes them feel stupid. When you do that, the service you're offering suffers.