About six months ago, Talking Points Memo publisher Josh Marshall had a realization.

It was something that had been bouncing around in his head for a while, but only then was he sure: It was time to formally deconstruct the idea of TPM as a website first — even though it was a website first, some 12 years ago when he started it.

“If someone were to ask me a year ago, I would have said, ‘Well, yeah, we’re not just a website — it’s this, and we have that, and the other.’ But I think it was when I saw mobile growing as fast as it was that it just sort of hit me at a different level,” Marshall told me. “Inevitably, as long as mobile was something like five percent of traffic, it was just something you made available on the side. But you start to see, this is going to be half of our audience. We can’t be approaching it in a way that the website is the thing, and we’re making imitations of it — because this thing is losing its primacy. In a lot of ways, it wasn’t until late last year that it hit me at a different level. It hit me as more than a concept. It was really true.”

“My only question is at what point tablets overtake smartphones.”

As of late March, mobile — smartphones and tablets — accounted for 19 percent of TPM traffic. By early May, when I sat down with Marshall in his New York office, mobile traffic to TPM had passed the 20 percent mark.

“I don’t have much doubt that that number will be 30 or 40 percent in the next year or two,” Marshall said. “My only question is at what point tablets overtake smartphones.”

So what does this realization mean, from a practical standpoint, for TPM?

“More than anything else we had to shift our own thinking, because that was constraining with how you do things on mobile,” Marshall said. “Realizing that TPM is not a website — it’s a bundle of knowledge and expertise and ongoing coverage that exists inherently on no particular platform, and we are consitently trying to find ways to make it adaptable on as many platforms as possible.”

But the rethinking process also means rejecting the idea that TPM content can be one-size-fits-all, which deputy publisher Callie Schweitzer calls “a game-changer for all publishers.”

“We’re giving a lot of thought to three different kinds of consumption: Active consumption being at the desktop, on-the-go consumption being on your mobile phone, and passive consumption being in your bed, on your tablet, something like that,” Schweitzer said. “For me, it’s literally about the physical way you’re doing it. You can certainly actively consume at all of those different places but when you’re reclining, looking at a beautiful visual on an iPad, it’s very different than being on a mobile phone or sitting at a desktop.”

It’s with this kind of thinking that TPM is approaching its election-year coverage, and another expansion planned for next year. In June, TPM is set to launch some new “basic features to make election coverage awesome.” Over the course of the next year, Marshall says they’ll roll out “some mobile-only stuff” (and that’s as specific as he’ll get for the time being). In 2013, you can expect new verticals that will fall broadly into categories like business, technology, and telecommunications. The mobile shift is also a driving factor behind TPM’s decision to return big to video after scaling back in the past.

“There are some places that video can go that text can’t, and there are times of the day that you watch things,” Marshall said in a later conversation. “We’re taking that bundle of ever-evolving knowlege and expertise and putting it into a video format. It’s all part of that same rethink…That’s the core reason we’re making such a push back.”

With the launch this month of weekly mini-shows like The Set-Up (Mondays), Polltracker Crosstabs (Wednesdays), and The Wrap (Fridays), TPM is delivering bite-sized news and analysis with the quality production sheen that some smaller news outfits forgo.

Each show is about three minutes long, which Marshall says is the “logical attention span.” Here’s an example:

“These are supposed to be quick updates on contained questions, so we think that’s sort of the sweet spot,” Marshall said. “We’ll do some longer than that…but we think that’s sort of the normal length. You don’t write a 5,000-word op-ed in The New York Times, and you don’t write a 300-word profile in the New Yorker.”

Political coverage is TPM’s bread and butter, so as the election season progresses, Marshall says there will be more and different kinds of video. That includes live video from conventions and election night, as well as video interviews with newsmakers. Marshall says he’s been wanting to get TPM back into video for years.

“We were heavily involved in original video in 2007 and 2008,” Marshall said in an email after our initial interview. “I did a daily show for almost two years. The reason we ramped back was because it was a strain on our staff capacity — there were many fewer of us back then — and we didn’t feel like the video ad market was mature enough for us to effectively monetize it. Now makes sense basically because both things have now changed. We have a much more robust video production capacity now. So it’s not so deeply reliant on me the way it used to be. The other part of the equation is monetization. Certainly lots of sites have been running pre-roll for a long time. But until relatively recently, the market for pre-roll for us was just spotty.”

In recent months, that’s changed “dramatically,” Marshall says. After growing his staff in recent years, he now has a combined force of 28 full-timers between TPM’s New York and Washington offices, and the ad revenue is available to help foot the bill. (Most videos are preceded by 15-second pre-roll ads.)

“If you look at the third-party studies that ad agencies look at, there’s just a lot of great data about how much more powerful pre-roll advertising is,” Marshall said. “Basically one of the big triggers why we’ve moved ahead [with video] is because — whereas in the past the market for pre-roll video was kind of inconsistent, now it is very different. Even in the last six months, it’s changed.”

Yet video ad revenue remains a relatively small piece of the pie, and Marshall says he expects it will stay that way because “so much of endemic advertising is non-video, the things on pages.” He views the growth of mobile and video as simultaneous more than causal, but both drive home the same point for him: News organizations need to embrace the idea that “disruption is the norm now,” and explore content distribution through multiple channels.

“Hypothetically, if you have, say, six basic platforms and maybe one of them accounts for 75 percent of your revenue — as a publisher, you don’t know how that mix is going to evolve as things go forward,” Marshall said. “In the same way that mobile has gone from low single-digits up to almost a quarter of our audience, it’s very important to have good profit margins and a good model across a bunch of platforms because you wouldn’t want the platform that you have not invested in to be the one that people go crazy for. That would be perilous.”