[mLuby]

In terms of raw skill, I'd expect introverts to come out on top, for the sole reason that they have likely put more hours into coding than extroverts.

On the flip side, more extroverted programmers probably do better when it comes to working on a team and project planning.

Ideally you're hiring a balanced team so they can cover each other's weaknesses.

[gnome_chomsky]

I don't think introversion or extroversion has any correlation to programming skill. And that is coming from an introvert. When it comes down to it, after many years in industry, I think that being extroverted is an advantage because this is an extrovert's world. And I have worked with several incredibly intelligent and savvy extroverts. Of course, this is all just anecdotal.

[gtaylor]

I have not seen a strong correlation either way. It's all a game of generalisations and tradeoffs.