Although the HRC campaign continues to beat the drum that superdelegates, voting their conscience (?), will be counted on to deliver her the eventual Democratic nomination, that tide has been running in exactly the opposite direction for some time now.
I've followed the trend on the Politico Superdelegate page.  HRC has gone from being almost 100 superdels ahead of BHO in January, 2008, to dead even shortly after the NC Primary, and now trails by 28.
The most recent cascade of commitments has resulted in another interesting stat ... BHO has a superdelegate edge in every category of superdelegates now (Add-ons, Congressional, DNC, Governors, Representatives, Senators), except for 'Distinguished Party Leaders'.
HRC has the same 9 'distinguished' endorsements that she's had since the Cloak of Inevitability was still draped upon her.  BHO has 5.  5 remain uncommitted (which must include Brother Al and Jimmy Carter, but I don't know who else).
So, on balance, the only 'distinguishing' characteristic of this segment of superdels is that they're out of step with the remainder of the party.