I hear a lot of frustration about the fact that many superdelegates are still staying publicly neutral. Many of Colorado's superdelegates, including Mark Udall and the brothers Salazar, are remaining uncommitted for the time being. All this despite Howard Dean's demands that superdelegates "decide now!", which sounds increasingly like my dad yelling from the driver's seat, "You kids quit fighting or so help me I will turn this car around!"
So why aren't they pledging? The main reason is that the superdelegates do not think as a unit. They could end this nomination today if they decided as a group, but they are individuals, and no one individual can end this today.
Moreover, they are individuals with their own needs and agenda. Many of them are members of Congress, nearly all of whom are running for reelection this year. If they're running, they need money from loyal party donors. As soon as they pledge to one candidate, they piss off half the party. Why do that before you have to if it just makes it harder to raise money?
Also, as soon as you declare for a presidential candidate, you become a lot less interesting. I imagine quite a few of these superdelegates are enjoying the attention they're receiving from the Clinton and Obama folks. Life gets a lot quieter after they make the call.
Finally, there's always the chance they could make the wrong call. There's still a few weeks of elections left. There's not likely to be any radical disclosures in that time, but it's always possible that Obama will turn out to be a gay communist or Hillary will turn out to be a reptile sent to this planet to drain our water, so why make the call before you have to?