Twitter's figured out second screen: McNealy

What's the next big tech trend?
What's the next big tech trend?

Former SunMicrosystems boss Scott McNealy says he's offered "condolences and congratulations" to Twitter CEO Dick Costolo about the social network's IPO plans.

"There's nothing more constraining than dealing with ... all the just crazy things we do to our public companies," McNealy told CNBC's "Squawk Box" on Tuesday. But he added that going public can also be satisfying.

(Read more: Twitter IPO: 'Gray market' indicates appetite high)

McNealy is part of the old-guard in Silicon Valley. He co-founded Sun in 1982, and sold the company to Oracle in 2010 for $7 billion. The move added hardware to Oracle's giant database and business-software businesses.

Twitter has figured out the second screen, McNealy said. "The 140 characters is perfect. TV is kind of a lean back experience, but if you lean back too far you fall asleep. It allows people to engage in achievable bite-sized 140 character moments."

As for whether Apple is in slump, McNealy said, "It's always hard to follow the culture … of a very successful CEO. Steve [Jobs] was incredible. And probably the only guy who's done it many, many times as opposed to be an accidental empire."

Addressing the rumors around Ford CEO Alan Mulally as a possible successor to Steve Ballmer at Microsoft, McNealy said he could see it—pointing to another great tech leader who came from outside the field. Lou Gerstner, former RJR Nabisco CEO, turned out to be the "best thing that ever happened to IBM."

McNealy added that while Microsoft has not called him, if he were CEO there he'd "probably move the company a little more open … and start sharing and the rest of the world to help me."

"Like Google, if you look at what Android is doing to the iPhone, boom, it's going right by it because it's mankind versus Cupertino," he said.

McNealy also announced during his appearance that his new social media start-up, Wayin, has partnered with Twitter. "We're heavily invested in their success."

Wayin allows "you to curate and present your social media conversation around your brand or around your sports team or celebrity," he said. "We're building the graphics and the visualization of all that clutter out there and noise, and turning it into real live information."

He said that clients can take the Wayin modules and put them on their websites, mobile platforms, on television, or "even at a venue—at a hockey game or football game. You can put it up on the big screen."

By CNBC's Matthew J. Belvedere. Follow him on Twitter @Matt_SquawkCNBC.