It’s been a hectic day for Don Graham and his niece Katharine Weymouth, kicked off by the announcement that Weymouth will be the new publisher of the Washington Post and the head of the new Washington Post Media group. When Graham, chairman and CEO of The Washington Post Company (NYSE: WPO), called from a cell phone this afternoon, they had already been to the online offices and one of the printing plants with Weymouth driving. She listened to our chat, then called back once they made it back to the office—before heading out to the printing plants again; today, in addition to buyouts at the newspaper, they also announced that the College Park, MD, plant will close in early 2010. It wasn’t a joint interview but even so, the two sounded very much in sync. We talked about timing, succession, integration—“no secret plans,” says Weymouth—and more.

Why now?: No trigger, says Graham. He wanted another senior exec in the sparse Washington corporate office in addition to CFO Jay Morse; the natural choice was Boisfeuillet “Bo” Jones, Jr., the 28-year WP veteran who succeeded him as publisher and CEO in 2000 and was appointed today to vice-chairman of the company and chairman of the paper. That dovetailed with the need for another kind of change. “Everybody at the Post and everybody at PNI has been tugging at my sleeve for the past year, saying some of these functions (should be handed over)—including (WPNI head) Caroline Little.” (He says Little continues to report to him on Newsweek.com and Slate.) The company is two-three times the size it was when Graham went up to corporate; having someone focus directly on this key part of it now makes sense. More after the jump…

Why Weymouth?: Graham reminded me that her background in advertising is the traditional route to publisher. “What Katharine is really doing is going into the seat I’ve been in where the newspaper and washingtonpost.com report to her. .. She’s uniquely equipped to do those jobs.” And, he adds, she has had “way more” print and digital experience than other senior execs. She has history with Little, dating back to Weymouth’s stint in the counsel’s office at WPNI. “They have an extremely good relationship. They’ll take a look at the reporting relationships.”

Weymouth says she can’t recall when the decision was made, calling it a gradual process. “We meet weekly and have for years.”

Weymouth as possible successor: I asked if this also places Weymouth in the role of his likely successor. Graham’s quick reply: “She’s only been at this job for an hour.” Besides, he’s not going anywhere anytime soon. Weymouth: “I think the answer is people have always speculated… I don’t worry too much.”

Digital: Graham first described digital as “our future,” the backed up a little and said, “a big part of our future.” Weymouth’s new job is to manage that “transition from a world we know very well to a world that’s changing.” The real unknown: “what it’s a transition to.”

Integration: I speculated earlier today that this could be a move toward integrating the business sides of the paper and the site while continuing to keep editorial separate. Weymouth: “I have no secret plans that go into place tomorrow.” Instead, she says, “My approach is going to be to talk to as many people as I can at both and get a feel from there what works well separately, what doesn’t. ... We’re pretty confident that there are areas that really make sense to be separate.” They want to be able to “be nimble and react quickly.” But when I asked if it would remain separate no matter what, she replied: ”I won’t say ‘no matter what’ to anything… you never know.”

Media Group: Weymouth is just beginning her own transition from focusing on advertising to running the much larger operation so it was far too soon for her to focus on specifics like how the print newsroom’s journalism is accounted for when it’s on washingtonpost.com. But she said that’s one of the reasons to “think of ourselves internally” as a media group. “They’re separate legal entities but also one, in the sense that the bulk of the content is generated in one newsroom.” She didn’t volunteer it but it sounds like she came up with the name for the new unit. In advertising, where they sell everything from the the Washington Post print and online to The Onion and Slate, their business cards already read Washington Post Media.  The name recognizes what already exists.

Can’t cut to success: Weymouth: “It’s no secret the newspaper industry is going through seismic changes. The buyout is one measure to cut costs… humanely.” But, she adds, “At the same time, everybody knows you’re never going to cut your way to success.” Finding new revenue streams is a top priority. I asked how long it would be before digital is half of revenues. She repeated that the future is in digital but wouldn’t forecast. “It depends on how quickly it grows.”

And that now depends, in no small part, on Kay Graham’s granddaughter.