Superdelegates are party officials and elected Democrats who are permitted to attend the Presidential convention and vote on the nominee even though they have not gone through the primary/caucus selection system. They are not bound to any particular candidate, although they can endorse whoever they please. Here is the official description of who superdelegates are, as found on the Democratic Party website:
At present the total number of delegates to the Democratic Presidential Convention will be 4,049. That includes 3,253 delegates selected by either primary or caucus from the states along with 796 superdelegates. Superdelegates thus make up 19.66% of the total number of delegates at the convention. [These numbers exclude all delegates from both Michigan and Florida because the Democratic Parties in those states scheduled their primaries earlier than permitted by the Democratic National Committee. The convention will have the power to reinstate those delegates should it be considered desirable.]
- The individuals recognized as members of the DNC (as set forth in Article Three, Sections 2 and 3 of the Charter of the Democratic Party of the United States); and,
- The Democratic President and the Democratic Vice President of the United States, if applicable; and,
- All Democratic members of the United States House of Representatives and all Democratic members of the United States Senate; and,
- The Democratic Governor, if applicable; and,
- All former Democratic Presidents, all former Democratic Vice Presidents, all former Democratic Leaders of the U.S. Senate, all former Democratic Speakers of the U.S. House of Representatives and Democratic Minority Leaders, as applicable, and all former Chairs of the Democratic National Committee.
The website 2008 Democratic Convention Watch is keeping track of which superdelegates have endorsed which candidate for the Democratic nomination. CNN Politics.com is performing a similar function. The two differ slightly but not significantly in the number of superdelegates each candidate has.
At the moment, Hillary Clinton has about 210 delegates to Obama's 123 and Edward's 52, with the magic number of 2,025 as the number of votes that will determine the Democratic nominee.