it could mean as many as 19 delegates, which was the sum total of the massive gold mine of delegates that he struck after spending millions and millions of dollars, and four years of his life (if you assume, as I do, that he began running for the 08 nomination before john kerry actually finished his 04 concession speech).
but even that is irrelevant. obama is going over the top on the 20th, and that would have happened with his endorsement or without it.
what his endorsement DID accomplish was to draw the media's attention away from the a$$ kicking that obama suffered in WV.