Is it better to be insecure than introverted?

I'm going to pick the 10 winners of the book giveaway on FlowerDust tomorrow, and I have learned a lot through reading the commments on Anne's post.  Here are the two things that most stand out to me:

1. There is a lot of confusion about what introversion is.  I think a lot of people assume that if they are comfortable socializing or feel the need to be around people then they must be extroverts or else riding the line between introversion and extroversion.  Of course, they may be extroverts or somewhere in the middle, BUT it's important to keep coming back to this: introversion/extroversion is primarily determined by energy source. Do you find it primarily in solitude (or in good conversation with a close friend) or in community?  Introverts can be very effective communicators and at ease among people, just as extroverts also need time alone.  But crowds will drain introverts after a while and solitude will drain extroverts after a while.  The farther you are on one side of the scale, the less need/desire you will have for the opposite.  But if introverts are loners or antisocial people, it's not because of their introversion!

2. It almost seems that people are more comfortable defining themselves as "insecure" or "shy" extroverts than they are with the label "introverts."  Anne Jackson realized that she is probably more of an "insecure extrovert" than an introvert, and I'm sure she's right about that.  But I would also guess that some of the commenters who also want to call themselves insecure extroverts actually fall on the introverted side of the scale.  But my question is, is the cultural bias such that people would rather call themselves "insecure" than "introverts"?!