Given that the tradition ladder-like, hierarchical approach to running companies is now running its course, then the next iteration is to view leadership as concentric circles. The individual (me) is always at the centre. I am influenced by those things positioned closest to me.
As per web 2.0 models, you can't "make" me put you in the circle closest to me. You can show me value and progress to my inner circles.
As per web 2.0 models, I will try and extend my leadership/influence to outer rings as far as I can.
All folks' circles overlap.
A great leader, senior in an organization, can influence me if I believe in them or value their influence - they need to embody the company credos for me to believe in the company credos. The value is in the individual rather in than in any company credos.
Thus peer2peer networking and mentoring is all about leadership. (see Oct. 08 Peer to Peer and Feb. 09 Why a Circle?)
Oh how many bottles of wine could we finish while debating this question!