Greg Beyer, an editor at the Huffington Post, sent an email to colleagues on Friday explaining why he passed on a pitch from a reporter who flagged a New York Times story about Uber. He had cited a company partnership with Uber as a rationale for rejecting the pitch.

Mr. Beyer's email telling a reporter to "hold on this one please as we're partnering with Uber on our drowsy driving campaign" was reported Thursday by Washington Post media blogger Erik Wemple.

The Huffington Post said Wednesday that Editor in Chief Arianna Huffington was joining Uber's board of directors. The revelation a day later of Mr. Beyer's email seemed to undermine the Huffington Post's argument that its newsroom could still cover Uber impartially.

Mr. Beyer apologized via Twitter on Thursday but went further in his email, which was obtained by Ad Age, and explained why he responded the way he did. He apologized for the decision, and said that he was in no way influenced by any other actors in making it:

HuffPosters, many of you have no doubt read news accounts of an email I sent about an Uber story a few weeks ago. I'm on vacation until Tuesday, visiting my family upstate, but I wanted you to have the full story.

As you all know, like any news organization, we send and receive a lot of emails. It's one way we talk to each other, and central to the way we do our jobs. We pitch and file stories, share ideas and updates. These exchanges -- containing all the questions, clarifications, and debates you'd expect in a fast-moving digital newsroom -- eventually become stories, videos, series, global conversations. That is, they become what people think of when they think of The Huffington Post.

Most of these emails fade when the story runs and the day ends. Some don't.

On April 6, a HuffPost reporter sent an email flagging a story reported in The New York Times, about an Uber driver who took a nap in his car, while his passenger took the wheel and led police on a chase.

Something clicked when I read that email. HuffPost had recently -- about 24 hours before, actually -- launched a campaign in partnership with Uber, stating our shared commitment to raising awareness around the dangers of drowsy driving. The Times article mentioned and linked to Uber's corporate statement on the drowsy driving campaign.

A few minutes after the reporter's email, here's what I wrote:

Let's hold on this one please as we're partnering with Uber on our drowsy driving campaign.

I didn't send it just to the reporter. I sent it, via "reply all," to a sizeable group of you, including our Crime editors -- who were the intended audience, given the nature of the story.

In the days that followed, several friends and colleagues in the newsroom pulled me aside to talk about it and also brought it to the attention of Arianna, who was not on the email thread. Arianna spoke to me as soon as she found out, and told me what I already knew: that my email completely contradicted what we stand for at HuffPost. She also asked me to send an email to the same thread, to acknowledge my mistake, apologize and reiterate our editorial guidelines.

I agreed. I understood. Following that conversation, I sent this note to the same group that had received my initial email:

Hi everyone, just wanted to bump this because a few people have asked me about this email and I realize it gave off the wrong impression. Obviously our partnerships never affect our coverage, and I was moving quickly in the moment and sent the wrong message as I read it in hindsight. For any confusion or concern I caused with my note, I apologize.

I've had a lot of time to think about my initial email. And now that interest in it has moved beyond HuffPost into the wider media world, I'll take the opportunity to expand on what I wrote to some of you.

Here's what that initial email was: a message written in haste that contradicted a basic journalistic principle and the ethos of The Huffington Post specifically.

Here's what it wasn't.

It wasn't an email sent with the input or influence of anyone else -- not Arianna, not my fellow HuffPost editors, not anyone.

It wasn't an attempt to protect or give a pass to an outside organization.

It wasn't an institutional statement or mandate about HuffPost's coverage of Uber (or our coverage of anything). Indeed, we ran a video about the story on the same day.

This past Tuesday, one day before the official announcement, I learned -- along with several other HuffPost editors -- that Arianna was joining Uber's board. My Uber-related email has now been interpreted by some as an attempt to water down our Uber coverage in advance of that announcement.

This is false. My newsroom email was sent nearly three weeks before I or anyone else in the newsroom learned about Arianna joining the board.

The only thing left is an addendum to my apology to colleagues, for whatever distraction this has caused from a great deal of very good and principled work -- including about Uber, but that's just a small part of it. HuffPost's willingness to report critically on advertisers -- and yes, on Uber too, over and over again, including work published this week -- is well documented. That's what we do, and what we'll continue to do. Best of all, it's a body of work, built by many people over many years, that can't be diminished by one editor's dumb email.

Greg