I think people expecting a more defined ending to the Democratic race tonight will be disappointed:

Once he reaches the magic number of 2,118, Clinton will acknowledge that he has secured the necessary delegates to be the nominee.
The former first lady will stop short of formally suspending or ending her race in her speech in New York City.
She will pledge to continue to speak out on issues like health care. But for all intents and purposes, the two senior officials said, the campaign is over.

So why will Clinton "stop short of formally suspending or ending her race"? Because she's still in search of "the perfect wave" -- some scandal that will make Obama unelectable, to come out between now and late August. And that's what will make it an endless summer.