There are very good odds that you have frequented MailOnline, which has come seemingly out of nowhere to become the most-visited newspaper website in the English-speaking world and No. 2 in the U.S., trailing only The New York Times in visitors.

It's winning the web with unexpected, surprisingly long headlines such as this one, the lead story on the site at noon on Thursday: "The scariest job interview ever! LG terrifies applicants with meteor crash through 'window'… that was really an ultra high-definition TV."

But even after the site, part of U.K. media conglomerate Daily Mail and General Trust, established a beachhead in the U.S. with new hires and $50 million from the parent company, it remains relatively poorly understood here. So we've rounded up 10 things you didn't know about MailOnline but should.

1. MailOnline considers itself the antithesis of BuzzFeed.

More than 600,000 unique visitors stop by MailOnline's U.S. home page daily, while more than 2.2 million do the same for the U.K. home page, according to ComScore. Roughly 40% of its U.S. traffic, and half its U.K. traffic, comes through those front doors, MailOnline says. That figure is closer to 25% at BuzzFeed, according to a person familiar with the site's traffic.

BuzzFeed is about viral content, something MailOnline certainly appreciates, said Martin Clarke, publisher of MailOnline."But really what we're about is the big homepage," he said. "We do stories that we think are going to work on our home page, which is why we don't do '31 Things To Do Before Breakfast.'"

(BuzzFeed Editor in Chief Ben Smith defended the site's emphasis on social media. "He's right that we're doing opposite things: we're trying to create great content that people are proud, not embarrassed, to share," he said in a statement.)

2. Its advertising has a long way to go in the U.S.

MailOnline expects global digital ad revenue to grow 59% to $72 million this year, the company said.

It declined to break out ad revenue in the U.S., but it's safe to say that the vast majority of advertisers on the site are based in the U.K.. Now MailOnline wants to cash in on all its new U.S. eyeballs through a better mix of display, native, video and mobile ads, including interstitial ads to run in image galleries on its mobile site and app. The U.S. site has already carried ads from ABC Entertainment, Fox, Burberry, British Airways and Unilever.

"We invested first in the editorial to continue to build the audience," said Mr. Clarke. Now, he said, it's about building the advertising presence.

To that end it is introducing its first ad campaign aimed at attracting U.S. advertisers, an effort from the New York agency Starfish that it says will run more than $1 million and use the tagline "Seriously Popular." The first ad, which will appear in industry publications including Ad Age, shows Kim Jong Un and Kim Kardashian with the text: "The Kims. They're On The Same Page."

"The ads are designed to be fun but evocative, like our home page," said Sean O'Neal, global chief marketing officer at MailOnline, hired last December from Nielsen.

3. It's part of a much bigger British invasion.

MailOnline is one of the latest British entrants to the U.S. news market, joining the Guardian and the Financial Times in a U.K. wave enabled by the web. While the Guardian and Financial Times aim for major scoops and thoughtful analysis, MailOnline publishes a blend of breaking news, celebrity gossip and offbeat stories that come mostly from aggregating stories from across the web. "We've built this up by doing things our own way and it works," said Mr. Clarke, publisher of MailOnline.

In addition to Mr. O'Neal, MailOnline in December hired Rich Sutton, who had led global ad sales at CBS Interactive Music Group, to be its chief revenue officer. Both executives are based in New York. The company now employs about 80 people in the U.S.

4. The company is not planning a U.S. print edition.

MailOnline sprang from the Daily Mail, but Mr. Clarke said he'd need to become "a real masochist" before a U.S. print edition hit Stateside. The site's American competitors are digital sites like The Huffington Post, he said: "In the U.S., we consider ourselves more a pure digital entity than a newspaper."

5. The site publishes more than 600 posts a day ...

And one of the posts from 2011 made an erroneous claim about Ad Age, reporting that an Ad Age poll had found an Armani ad with Rihanna the sexiest of the year. The problem was that Ad Age never conducted such a poll. At the time, MailOnline said its source was a press release from TNI Press Ltd. The story created significant buzz -- it inspired The Huffington Post to create a slideshow -- despite the lack of an available Ad Age story to link back to. The MailOnline story is still live. "When you publish more than 600 stories a day it's not completely out of the realm of possibility that something like that happens," said Mr. O'Neal. "We're quite proud of the overall site."

6. … But the newsroom seems surprisingly quiet.

Reporters in MailOnline's New York offices -- located in the city's trendy SoHo neighborhood -- sit nearly shoulder to shoulder at 50 work stations spread across several tables. The atmosphere at least on one visit was far more sedate than you'd imagine, with few conversations to be heard above the sound of typing. Thankfully for its cramped reporters here, the company has leased half the floor beneath to allow for more growth, Mr. Clarke said. "Where we need to go now editorially is to deepen our coverage, broaden it and get more expertise," he added.

7. You won't hear about any flashy reporter hires as it grows.

MailOnline is hiring, fast. Mr. Clarke splits his time between New York and London but spends much of it right now interviewing and hiring reporters in the U.S., not only in New York but also Los Angeles and Washington, D.C. And -- unlike some of BuzzFeed's prominent talent acquisitions -- none of them will be big names in journalism.

"I can get much more value by training our own people up from scratch than in spending a fortune on someone who already has a reputation," Mr. Clarke said.

8. The site reaches 19% of all U.S. women ages 25 to 34 online.

More than half of MailOnline's audience is female, the company said. And it is the second most-visited newspaper site -- behind The New York Times -- among women ages 25 to 34, according to ComScore, which says the site reaches nearly one-fifth of all U.S. women in this demographic. Among mobile readers in this group, MailOnline is the No. 1 newspaper site.

"Mobile is growing massively fast and, to be honest, it's an intrinsically more valuable audience -- they're spending more time and they're more engaged," said Mr. Clarke.

9. MailOnline doesn't cover sports in the U.S.

Mr. Clarke said MailOnline's current lineup of stories appeal to readers in the U.S. and U.K., but sports are specific to country. Both audiences want "football," but they mean decidedly different things to each audience. "At some point we'll have to cover sports in America," he said.

10. The U.S. site is operating in the red.

MailOnline is not profitable, but only by choice, according to Mr. Clarke. "If we weren't continuing to invest in growth in the U.S. and elsewhere, yes we would be," he said. "But we're deliberately not taking any money out. We're pretty much reinvesting everything in growth because we see this as a once in a lifetime opportunity to grow a new brand. In the scheme of things, it's not ruinous. What's more important to us is growth."