The hurry among the press and pundits to predict whether Hillary will or will not concede, and when, overlooks the question of incentives. Hillary's got an estimated $10 million campaign debt, she feels cheated and insulted, and Team Obama's got to offer something in return for her concession. If they don't want to deal -- say, a flat-out guarantee to pay off her debt -- then Hillary says, "Fine. I'll fight on. Whatever it takes."
Compared to running campaign offices and TV advertising in different states, it's relatively cheap for Hillary to maintain a post-primary skeleton campaign. She and her proxies just make the circuit of TV news programs with their "we wuz robbed" mantra, and the campaign continues. If Team Obama wants to convince her not to do that, they'll have to deal.
Hillary may surprise me and concede on TV tonight, but it would be a surprise.