http://www.mugglenet.com/jkrinterview.shtml

The most interesting part of the interview is when she talks about Dumbledore. She says he's really lonely. Which I never saw. Since the books only cover what Harry sees, I thought Dumbledore has a whole life we just didn't know about. Just based on his funeral people came from far and wide to be there. I thought he had a wealth of friends.

She also said she couldn't reveal information about Dumbledore like what he would see if he encountered a Bogart. Even though she said he's dead because Harry has to end the story himself, I think the fact that she wouldn't reveal personal information about Dumbledore means he's still very much a part of the story.