You know, I never noticed it. But then, I also didn't notice picture frame my mother had had up for months in her room. In my defense, I don't go into that room often, and I don't generally stare at the wall when I do. And the frames and walls are both white, I think. (^.^; )
the orange does seem to balance the mostly blue header and theme. it's pretty cool how something so small can have an effect on the impression you get just from a quick visual scan.
i would dare say that the orange square is at the very core of what mbti is all about. it is representative of the uniqueness we all feel after having discovered our types and the system. like most of us, it is a square surrounded by circles. an orange, surrounded by whites trying to maintain it's orbit without being swallowed up by the larger, more aggresive forces. a square, trying to avoid being forced into the life of a circle. the slightly tilted angle is significant as well. it represents how we're all slightly biased in one way or another. in this case, since the tilt is towards the center, the "mbticentrol" center that means we all have a keen interest or bias towards mbti compared to other personality systems. the oversized "m" and "b" letters behind everything represent the underlying rules set forth by myers and briggs. their ideas are the groundwork under which we have laid the foundations of this site. ideas truly larger than can be seen in one header. and lastly the colors are significant as well, the blue can be seen as water or a vast ocean of life from which the whiteness forms. the arcs or orbits, they are symbolic of the path life must and always will take. and of course, the orange is simply one of many colors that life can take on when it the light from mbti is reflected upon it. one might say that until you have embraced mbti one's true colors will never be reflected in oneself or to others.
hrm... or it could have just been a random photoshop accident. who knows.