There's an interesting tension between the ordinary hierarchical structure of the campaign organization and it's more egalitarian mass base. The VP vetting committee consists of a small inner-circle at the top. Under "ordinary" circumstances, we would expect some initial spreading of the news through a few other levels of inner-circle, but, apparently, that won't be quite how it works:
"…Mr. Obama’s deliberations remain remarkably closely held. Aides said perhaps a half-dozen advisers were involved in the final discussions in an effort to enforce a command that Mr. Obama issued to staff members: that his decision not leak out until supporters are notified."
And even the future VP nominee is not in the loop:
"Mr. Obama had not notified his choice — or any of those not selected — of his decision as of late Monday, advisers said."
Some of these considerations are purely instrumental attempts to maximize media impact, of course, but there's relational information in them thar hills too: each player learns where s/he stands in the information order and can decode this to ascertain where s/he stands in the pecking order.