Just when it seemed there were no corners of the media world left for the celebrity-industrial complex to colonize, Twitter has gone celebrity-crazy.

As early adopters like Kevin Smith, Greg Grunberg, Lily Allen, LeVar Burton and of course, the First Couple of Twitterdom, Ashton Kutcher and Demi Moore, have racked up followers, their tweets have created a new kind of aura: accessible, yet protected by the boundaries of cyberspace.

These stars understand the potential of the new medium to promote themselves without seeming self-promotional.

Fans, meanwhile, are scrambling to figure out which celebrities are worth following, helped by sites like Celebritytweet.com [1] and feature articles like “25 Twitter Must-Follows [2].”

As BeBe Lerner, a publicist at ID-PR, put it, "Based on the amount of media attention they have received in the past few weeks, it seems like Twitter got a publicist.”

And the micro-blogging service is, by its very nature, changing the rules of the celebrity game in ways that publicists -- like the rest of us -- are being forced to adapt to.

For starters, there's the direct access fans have to celebrities via Twitter. For years now, celebrities have had to wall themselves off from their fans to protect their privacy -- if not their very lives. “Communication” came via strictly-publicist-approved entertainment journalism.

It’s become conventional wisdom that over-control by publicists has dealt a heavy, perhaps even fatal blow to entertainment journalism, a genre that once boasted classics like Gay Talese’s famous profile, “Frank Sinatra Has a Cold,” but in recent years has become an embarrassing cookie-cutter form in which heavily guarded celebrities can be counted on to mouth mainly banalities.

But Twitter gives the impression of freshness and spontaneity to a star’s words.

One big factor is that on Twitter, anyone can ask a star questions. The star is free to be his or herself without fear of stalkers, protected by the “wall” of their Twitter account. They often answer fans’ questions, in a tweet that only the fan will understand, like this one [3] from Jimmy Fallon to a fan who must have offered some point of criticism or suggestion to the “Late Night” host:

“@drinkosmosis they are cue cards. We use cue cards so that we can change it fast last minute. I see what you're saying … I'll work on it.” (For more stars' tweets, see accompanying story. [4])

Cute, right? It’s all part of the feeling that Twitter is a fun little cyber-village, its inhabitants all, somehow, friends.

But if you think that means the publicists have been sidelined, think again. Power publicists are striving to make their clients understand that their tweeting is not just some innocent personal expression.

The smarter celebrities are getting it, making their Twitter identities just one part of their overall media strategy -- which means, inevitably, that it’s controlled to some degree by their publicity team.

Britney Spears’ Twitter [5] is an extreme example: Some tweets are attributed to “Adam Leber, Manager,” some to “Brit” herself. Some look like ads for Spears’ website:  “Photos of Britney and her dancers at Tribe Hyperclub in Montreal. See them all at http://britneyspears.com.”  [6]

It’s not a huge leap to question whether the “Brit” posts (such gems as “Just want to thank all of my beautiful fans for making me number 3 on Twitter! Love you guys! -- Brit”) are actually thought up and typed in by Britney herself.

But some celebrities appear to have genuinely taken to the medium, finding a voice that seems authentic to them -- whether or not they have a publicist’s help. “Star Trek: The Next Generation” web icon Wil Wheaton, for example, who excels at self-revealing posts like this one [7]: “Uh, I don't have and didn't make millions from movies and TV. I was on TV before they were giving out that kind of money to guys like me.”

But he’s also willing to put a little friction in the mix, too, when a fan goes too far [8]: “@SandiegoBill I tell you what: how about I just save us both the headache and block you, instead? Pro Tip: Don't be a dick, dude.”

“You have to have a personality on Twitter, and it has to reflect your brand,” said veteran publicist Howard Bragman, author of “Where’s My Fifteen Minutes?” Bragman said he tells clients to “have a reason” for each tweet.

“You have this direct contact with an audience,” Bragman said. “But there can be a loss of control with regard to the message.”

What drives the publicists nuts is the potential for celebrities to fritter away their fans’ attention with information overload. It’s a real question in the age of Twitter: Are celebrities inviting us in to their lives, simply in order to bore us to death?  “It’s the What I Had for Breakfast Syndrome,” as one put it.

“In one way it feels small and personal, but celebrities have to realize that there is always going to be a huge public eye on what they’re tweeting.”

But for now, the potential for Twitter to not just make fans happy but to actually help rebuild careers and images has publicists jumping on board.

Twitter success stories include “CBS Evening News” anchor Katie Couric, whose career resurgence has coincided with her Twittering.

“Twitter has been part of a multi-platform digital expansion for Katie and the ‘Evening News,” said Matt Hiltzik, Couric’s rep and the president of Hiltzik Strategies. “It’s been one component of a concentrated effort to reach viewers beyond the traditional formats, and it’s actually been quite well received,” Hiltzik said.

Then there’s MC Hammer [9], whose career has been in recession but who’s been building up a following over the last year for his Twitter feed -- a lively mix of inspirational thoughts, updates on his activities and appeals to help his various causes.

When he recently tweeted to Ellen DeGeneres that he wanted to come on her show, she invited him. He appeared yesterday [10], and the two sang the praises of Twitter.

“I like it cause it takes away the velvet ropes,” Hammer said.

It was an event made possible only by Twitter. “Can you imagine if MC Hammer just e-mailed Ellen and asked if he could come on the show?” as one publicist put it. “Never would have happened.”

For now, with celebrities and Twitter, it’s the honeymoon phase.

“It’s a symbiotic relationship,” said Adam Isserlis, who handles digital media at Rubenstein Communications. “Twitter is the rising tide that lifts everyone’s boat, and in turn, all these celebrities are helping Twitter.”

Even potentially negative events like the hijacking of a celebrity’s identity have turned out all right in the end.

When Shaquille O’Neal had a hoaxster Twittering under his name, his publicity team at the Phoenix Suns convinced him to start tweeting himself -- and “The Real Shaq [11]” became one of the most-followed Twitter feeds, with Shaq responding to a staggering number of his fans’ queries every day.

And, as TheWrap reported yesterday [12], the feed apparently belonging to Christopher Walken [13] is among the most popular on Twitter but is not written by the actor himself -- though, if anything, it’s so well done that it’s rallying the actor’s fan base.

And when Mischa Barton decided to take back her Twitter identity from a fan who had been fake-tweeting as her, she was downright polite about it:

“@mischabarton I appreciate your keeping people updated with whats going on on ‘my’ life, but I think I’d like to do my own twittering now.”

She'll be tweeting as TheRealMischa from now on.

Still, it seems inevitable that something will go wrong at some point. It seems natural to expect any day now the first genuine Twitter PR disaster.

The possibilities are many. It’s not just that a star could turn off fans with a few impolitic words. It could get much darker. As one publicist mused, it’s only a matter of time before some fan commits some deeply troubling act and claims he was led to it by a celebrity’s tweet.