While we imagine Richard Johnson and Paula Froelich sometimes raise their voices at each other in between telling off publicists, the type of Page Six infighting we're really enjoying is happening at their struggling dot com.

The three-month-old PageSix.com just pointed toward the exit sign with Sean Borg, the "mover and shaker’ on the London social scene," as he calls himself on his website, and all-around opportunist. After spending just a few months with the gossip website, Borg fell victim to his own success … in running his mouth.

And he had a little problem, some say, being a little too imaginative with his gossip stories. Those who know Borg might call him a "master two-facer," and we've heard plenty of anecdotes to explain the superlative.

From sucking up to managing editor David Boyle (Borg has told peers they're very good friends) to trashing him privately, to pretending to befriend colleague Jen Heger only to go round after round with her under the radar (trashing her to coworkers and anyone else who will listen), Borg is racking up frenemies. Nevermind, then, that Borg tells us he's still working there, at least in a small capacity; sources confirm he was given his walking papers earlier this month.

"Sean Borg is a nightmare," says a knowledgeable source. "He's a bully, a maniac. He bullies everyone he works with. [...] He has also verbally threatened his coworkers and often threatens to ruin them if they cross him."

Borg denies those charges, setting off this volley of he-said she-said.

In fact, he has only pleasant things to say about working at PageSix.com, where he arrived after a stint at TMZ. "It's a really good product. It's a lot different than TMZ and Perez." But, "as much as I love the creativity involved at Page Six, for me, it just doesn't work for me personally. I need to put my family first." (Borg, a Brit who keeps a residence there, tells us his father is ill, and he's been caring for him.)

Disappearing from the office for days at a time is also a reputation Borg developed. Explaining his absences, Borg says: "I travel back and forth from the U.K. a lot. It's very difficult to be in an office all day." (Don't we know.) "I go back to England for like three weeks at a time."

But if it's Borg's work habits that caused some strain, it's his hatchet job on his peers that has earned him persona non grata status.

"He's personally setting out to sabotage the career of Jen Heger, a good reporter," says one source. But from tales we've heard, Jen's been fighting back, too.

In a recent scenario, we hear it was Heger who took things up a notch, writing an unsolicited note to News Corp. human resources saying Borg was claiming expenses that weren't valid, and to look out for a huge charge from his Spice Girls concert at the Staples Center. (He saw the concert in a skybox that didn't belong to him, or News Corp.)

Responding to the claim, Borg asserts: "I had like 10 friends with me in the box. I never submitted [the bill to News Corp.] … It was not $700. It was a lot less than that."

But that's not to say having Borg on staff as a reporter comes cheap. When asked about his tendency to expense large sums, Borg says, "I hang out with elite people. You can't go to Mr. Chow [and not spend a lot of cash]."

According to Borg, however, he's not out to get Heger. "There's a healthy competition. Jen's really good at her job. I think she's proved herself quite a budding journalist. I don't really know her that well."

(As for Heger, who still works at PageSix.com, we hear she enjoys escapades of her own. Back when PageSix.com was fighting post-by-post with TMZ over Barron Hilton's DUI arrest, we hear Jen offered cash to the gas station attendant allegedly hit by Paris' younger brother if he refused to speak with the competition. Whether that cash was to come from her pocket, or Page Six's, isn't known.)

As for managing editor Doyle Boyle, who's been described to us as both "really really nice" and "overly demanding, it's ridiculous," it's clear he's feeling the stress of a minute-by-minute news cycle.

While sources at TMZ tell us they barely consider PageSix.com competition, an email Jossip obtained, from a third party, between Doyle Boyle and TMZ supervising producer Gillian Sheldon has Doyle Boyle lashing out at his biggest foe:

From: Boyle, David [mailto:XXX@nypost.com]
Sent: Thursday, February 21, 2008 3:14 PM
To: Sheldon, Gillian S.
Subject:

Hey Gillian

Are you guys so scared of Harvey that you have to backtime your stories? We posted Ashton Kutcher before you.

Somebody will write about it :)

(Doyle Boyle and Heger didn't respond to requests for comment. Sheldon had no comment.)

All this on top of "flaky" news director Jacki Gallo, who is said follow Borg's loose policy on going in to the office. There's also the saga of In Touch transplant and PageSix.com topper Kathy Campbell, whose tense relations with staffers and Boyle have kept tensions high, though she remains employed there.

What about staffers like Us Weekly transplant Noelle Hancock and Matt Donnelly? We're told they have avoided most of the internal spats. But what fun this spectator sport must be.

But don't think Borg is getting to caught up in all of this. "I go to work, I do the job, and then I have my separate life from that."