Zite, the personalized news magazine app for the iPad, adds an iPhone version of its application to the lineup today. The company, which we wrote about here and which was acquired this summer by CNN, has focused on making the semantically-intelligent app fit the smaller-size format of the smartphone, with one-thumb navigation, vertical story and left-to-right category view flow, and a focus on the facts of story name, title and source , rather than snippets, as starter views.

CEO Mark Johnson says a prerequisite for the iPhone app was its release of Sybil technology in late October, which allowed Zite to have multiple profiles that adapt to the reader’s preference. This made it possible to share the Zite app on a family’s sole iPad without messing up individuals’ preferences. It comes in handy for the new smartphone app because, “if you did all this work on your iPad training this very intelligent AI, you don’t want to lose that when you go to the iPhone,” Johnson says.

Johnson expects the iPhone app to appeal to existing iPad users. “Personalization is really addictive. Once you have it one place, you want it everywhere,” he says

. “The number one thing our users want is to have it on more devices.” But he also sees this release as reaching out to a whole new set of users, given that the iPhone market is bigger than the iPad space.

What next for Zite? Johnson himself is a Windows Phone 7 user (he used to work at Microsoft), for example – and it’s a market he expects to get even more interesting with Nokia in the market. “The goal over the next 12 months is to be on as many platforms as possible,” he says, and Windows phones are definitely on the options list. “Personally I think it’s a great platform – they’re doing innovative and interesting things I don’t see from Android or the iPhone,” he says. “But we’re going to be smart about which platform to go to next. We’ve got to go where the users are.”

Android continues to be the most popular smartphone OS in the U.S., with 43 percent of the market, according to Nielsen’s third-quarter smartphone report. But with its iPad heritage – plus the fact that iPhone users tend to download more apps – the iPhone was a natural next-destination for Zite. “Raw numbers don’t tell the complete story of usage patterns and why be on one platform vs. another” he notes.

Among other work that’s been underway at Zite recently has been the addition of new categories, including NHL for the hockey season. Alas, plans for an NBA category were put on the side given the players’ strike. Johnson also says the company has been doing a lot of work on language detection, so as not to deliver foreign language articles to those who don’t know the tongue, and in authoring detection, to help bring more of those writers that readers may have an affinity for to their notice. “Work is always being done on the back-end,” he says, to naturally inject more and more information focused on users’ interests without their having to set up and finesse that all themselves. Improving features on supported devices remains a high corporate priority. “The most important reason people come back to Zite is because they have an intelligent news-reading platform that gets smarter in the background, even if they don’t see it visibly every day.”

Zite continues to operate as a pretty independent company since the CNN acquisition, with the advantage that now it’s well-capitalized.  “CNN wants to see Zite be successful,” Johnson says. “And 90 days from the acquisition we’re launching the iPhone application, so we’re really keeping up the momentum.”