YouTube has become the de-facto launchpad for the next generation of celebrities, personalities, and big stars.

Well-known names like PewDiePie, Shane Dawson, and Smosh have racked up millions of subscribers over the years by uploading videos on YouTube and forming seemingly personal relationships with their fans. From comedians to gamers to vloggers of all kinds, YouTubers have harnessed the video-sharing platform to build their followings and brands from nothing more than a video camera and a solid internet connection.

To get a closer look into which stars rule YouTube, we looked at the SocialBlade rankings to see which channels have the most subscribers. We focused on independent YouTube stars, disregarding YouTube channels from mainstream celebrities and music record labels.

These are the YouTube personalities with the most subscribers:

Of all the status symbols out there that billionaires could use to flaunt their wealth, owning a private jet may be one of the most lavish choices.

Billionaires, like Richard Branson and Elon Musk, are often known for their crazy purchases. When you can afford to spend $80 million a year on average, you have the luxury of being able to drop millions for investments in items that the average person could never dream of.

A common purchase among billionaires are private planes. Having a private jet for quick and easy travel may be especially valuable for high-powered executives and investors who may need to be on the other coast that same day.

Here are some of the notable tech billionaires who own private jets:

When Amazon first launched in 1995 as a website that only sold books, founder Jeff Bezos had a vision for the company's explosive growth and e-commerce domination.

He knew from the very beginning, he wanted Amazon to be "an everything store."

In author Brad Stone's 2013 book on the origins of Amazon, he paints a picture of the early days of the company and how it grew into the behemoth that it is today.

Jillian D'Onfro contributed to an earlier version of this story.

With a name like "Smart Lock," you might think the Google feature has something to do with security, and is possibly powered by AI-technology. And while that's generally true, when it comes to Smart Lock, things aren't that simple.

That's because, in a somewhat perplexing move, Google decided to use the name "Smart Lock" for three separate tools that apply to different things.

Here's a breakdown of what Smart Lock does when it comes to Androids, Chromebooks, and passwords in general:

What Google Smart Lock does for Android devices

In short, Smart Lock keeps Android devices unlocked when they're in your pocket or you're close to home, or in another trusted location.

That means you won't have to use your pin, pattern, or password to unlock it. To activate it, you must have a screen lock already set up. Then, follow these instructions on your Android device to turn it on:

1. Navigate to your device's settings.

2. Tap Security and Location, then select "Smart Lock."

3. Enter your screen lock pin, pattern, or password.

4. Select either On-body detection, or opt to set up a trusted place (depending on your preference).

5. For on-body detection: On the next screen, simply switch that option on.

6. To set up a trusted place: Either let your phone use your current location, or turn on "high accuracy or battery-saving location mode" (you'll want to have Wi-Fi access for either option).

What Google Smart Lock does for Chromebooks

For those with Chromebooks, Smart Lock allows you to unlock your laptop using your Android device. You can also send and receive texts from your Chromebook.

You can use Google Smart Lock to unlock your Chromebook using an Android device. Acer

You'll need to have Chrome OS version 71 or newer, Android version L-MR1 or newer, and you need to be signed into your Google account on both devices.

Assuming you meet those requirements, here's how to turn it on:

1. At the bottom right of your Chromebook's screen, select the time.

2. Select "Settings."

3. Under "Connected Devices," choose the "Set up" option next to your Android device.

4. Enter your password and follow the steps when prompted (you'll get a confirmation message on your phone).

5. Under "Enabled" select the options you want to turn on.

You may get a prompt to set this up, in which case you'll only need to select "Accept and Continue" followed by "Done." You'll then get a confirmation message.

What Google Smart Lock does for passwords in general

Google Smart Lock can also sync your passwords across your various devices. So, provided it's on, you'll easily be able to sign into your Chrome browser or Android device.

On both Chrome and Android devices, the option to offer to save passwords is automatically turned on.

For those on Chrome, you can manage your passwords by going to your Google account, then select "Security" in the left sidebar followed by "Password Manager." From there, you'll be able to see, change or remove passwords that have been saved to your Google account.

Google Smart Lock also refers to the password manager used by Google Chrome. Devon Delfino/Business Insider

On an Android device, you'll manage your passwords by going to your "Settings," and clicking on "Google" then "Google Account." Next, tap "Security." Under "Signing into other sites," select "Saved Passwords." You can block certain sites or apps from saving your passwords under the section titled "Blocked."

Instagram is a cash-printing leviathan, estimated to be worth in excess of $100 billion on its own and widely viewed as crucial to Facebook's future growth. But it wasn't always this way.

Back in 2012, the 13-employee photo-sharing app was acquired by Facebook for $1 billion, in an eye-popping deal that was questioned by critics at the time but has since paid for itself a hundred times over.

In the days that followed, one of Instagram's cofounders, Mike Krieger, gave a talk at Airbnb's San Francisco offices about how he and Kevin Systrom, in under two years, built the photo-sharing app from nothing into a $1 billion business with 35 million users that drew the attention of one of the world's most powerful tech companies.

Krieger and Systrom have since left Instagram, but the presentation Krieger gave in April 2012 is still fascinating on multiple levels. It presents a unique window into the company's history, provides insight on the challenges behind going from nothing to huge so fast, and offers lessons to other entrepreneurs hoping to follow the now-legendary Instagram cofounders' path.

Business Insider has republished the deck of slides from that talk in full below.

A good mattress will last you for decades, and you'll spend a third of your daily life on it. When considering such an important purchase, you should be able to spend significant time sleeping on the mattress. Fortunately, Casper allows you to test drive all of its mattresses for 100 nights risk-free, and the company now has samples all over the country — at Target and in their own brick-and-mortar stores — for you to see and feel in person.

Recently, Casper updated its flagship mattress and introduced the Casper Hybrid mattress. The updated flagship Casper features a new zoned support foam layer that focuses on providing pressure relief and support that is firmer under the hips and softer under the shoulders.

The new Hybrid also has the zoned support layer along with the other three foam layers found in the updated Casper. What sets the Casper Hybrid apart is its individual coil springs designed to provide added lift and increased airflow.

Casper recently sent me both mattresses to test. Each has weaknesses and advantages. Below, we compare the updated all-foam Casper mattress to the Casper Hybrid mattress in a few key categories: price, style, return policy, warranty, set-up process, comfort, edge support, and motion transfer.

Keep scrolling to see how the flagship Casper mattress and Hybrid mattress compare:

Target faced massive technical difficulties on Saturday, as customers across the US found themselves unable to check out at the retailer.

At around 2 p.m. ET, Target customers at locations across the US began reporting malfunctioning cash registers on social media. Soon, long lines formed, as customers were unable to check out.

According to one Target employee who reached out to Business Insider, workers were told that the retailer was facing a global cash register outage. Other employees shared similar reports on social media.

Employees handed out free samples to frustrated customers.

Others asked that customers not lash out at Target workers — who were stressed themselves.

The systems issue — dubbed "The Great Target Outage of 2019" on social media — soon took on almost mythical qualities.

Some compared the incident to the disastrous Fyre Festival.

Some Target locations appear to have closed, citing a "Target global issue."

Target experienced similar issues exactly five years ago, on June 15, 2014, when a glitch caused cash registers across the country to crash for hours.

At around 5 p.m. ET, Target announced that registers are "fully back online."

"The temporary outage earlier today was the result of an internal technology issue that lasted for approximately two hours," a Target representative said in a statement to Business Insider.

"Our technology team worked quickly to identify and fix the issue, and we apologize for the inconvenience and frustration this caused for our guests," the statement continued. "After an initial but thorough review, we can confirm that this was not a data breach or security-related issue, and no guest information was compromised at any time."

HBO's gritty high-school drama, "Euphoria," could open the network up to an audience of teens and young adults that it's only flirted with before.

"Euphoria," one of the most anticipated new shows of the summer, is a depiction of modern life as a middle-class American teen that is as harrowing as any episode of the HBO crime drama, "The Wire." The series, which premieres on Sunday in the US, takes an unflinchingly look at the struggles of young adults, including sex, drugs, identity, relationships, and social media, through the lens of 17-year-old high-school student, Rue Bennett, who is returning to school and life after a drug overdose and summer away at rehab.

It's a different — and darker — take on a typical teen drama.

Despite its provocative depiction of high school, early reviews of "Euphoria" have praised the stunning visuals, performances by its young stars, including Zendaya, and direction. The series was created and written by Sam Levinson, who also directed five episodes of the season.

Such acclaim is rare for teen-focused shows. But it's not unusual for HBO, which had the most Emmy wins for 16 years running until Netflix tied it last year. HBO is mainly known for its boundary-pushing adult dramas and comedies, like "The Sopranos" and "Curb Your Enthusiasm."

Growing up, HBO style

Past HBO series like "Game of Thrones" and "Girls" have no doubt attracted young fans to the network, as have the kids and family programs that HBO has dabbled with, including recent seasons of "Sesame Street."

But the networks audience skews older.

HBO's five most watched shows live from the last 18 months were "Game of Thrones," "Real Time with Bill Maher," "Westworld," "Big Little Lies," and "Sharp Objects," according to Nielsen. The median ages of the 10 most watched HBO series live during that time were between 46 and 61, with "Game of Thrones" having the youngest and "Real Time with Bill Maher" having the oldest median age.

"Euphoria" speaks more directly to teens and young adults than other HBO series, such as "Chernobyl," about a 1986 nuclear disaster, or the family drama, "Big Little Lies." HBO is also trying its hand later this year at a young-adult fantasy series, "His Dark Materials," based on the Phillip Pullman novels.

The young-adult shows are hitting HBO at a time when the network is trying to grow its TV and streaming audience, after its parent company, WarnerMedia, was acquired by AT&T last year.

"The challenge is, not 100% of the customers expose themselves to the HBO brand," John Stankey, CEO of WarnerMedia, told HBO employees in July, after the deal with AT&T closed, Vox reported. "We've got ... to have this become a much more common product."

So far, growth at HBO's streaming service has been slower than at some of its competitors.

A May survey by RBC Capital Markets found that 21% of respondents in the US had watched HBO's online-subscription service, HBO Now, in the last 12 months, up from 18% a year ago. Rival services like Amazon Prime and Hulu had grown by double-digit percentage points during that time.

Read more: The share of Americans watching Amazon and Hulu has soared in recent months, while other streaming services lag behind

An adult show about teens

While "Euphoria" is about teens, the network says it's made for adults. It's meant to expose adults to the challenges of growing up in 2019, Casey Bloys, programming president at HBO, told The Hollywood Reporter.

Read more: HBO's upcoming teen drama 'Euphoria' is filled with graphic nudity, including a single scene that shows approximately 30 penises

Nonetheless, the show's cast and crew of 20-somethings is likely to attract a young crowd. Zendaya, a former Disney Channel star, who has since been in films like "Spider-Man: Homecoming," plays Rue. Hip-hop superstar Drake, who got his start on another controversial teen show, "Degrassi," executive produced the series. Drake and Zendaya have two of the 50 most followed accounts on Instagram, where they've been helping to promote "Euphoria."

The series is based on an Israeli drama set in the aftermath of a murder of a teen near a nightclub.

The HBO version grapples with controversial issues, in the vein of teen series like "Degrassi," "Skins," and Netflix's "13 Reasons Why" before it. But "Euphoria" has none of the comedic relief of "Skins" or the cautionary melodramatics of "Degrassi."

From the first four episodes, you might think that life as a modern teenager consists mainly of dick pics, webcam rendezvous, overdoses, and staying out all night, with a few forced family dinners in between.

"I was trying to capture the heightened sense of emotion when you're young and how relationships feel," Levinson, who created and wrote the series, told Entertainment Weekly. "The world feels like it's just constantly bearing down on you. That anxiety, and those sort of mood swings, I think, are inherent to being young — but even more so when you struggle with anxiety and depression and addiction."

Levinson struggled with drug abuse during his youth, and wanted to capture the pain of addiction, without also glorifying drug abuse. Many of the scenes in "Euphoria" are drawn from his own experiences.

"The hardest thing about portraying a drug addict is — there are a lot of cautionary tales, there are a lot of after-school specials — but what I really wanted to get to the core of is the pain and the shame about what you're doing and you're inability to get clean despite the havoc and destruction you're wreaking round you," Levinson said, at the ATX Television Festival, Deadline reported.

One person has died from an e. coli infection stemming from a poop transplant, and the US government is warning it could happen again.

The Food and Drug Administration on Thursday published a bulletin warning against possible complications from fecal microbiota transplantation (FMT), which has been rising in popularity for the treatment of C. diff, a debilitating gut infection.

"The agency is now aware of bacterial infections caused by multi-drug resistant organisms (MDROs) that have occurred due to transmission of a MDRO from use of investigational FMT," the FDA said.

"Patients considering FMT to treat C. difficile infection should speak to their health care provider to understand the potential risks associated with the product's use."

Dr. Sahil Khanna, a gastroenterologist at the Mayo Clinic who performs fecal transplants, told NBC News that it's likely the first death from an FMT procedure.

Still, the procedure can work just as well as traditional antibiotics in treating C. diff, which the Center for Disease Control and Prevention estimates infects 500,000 patients every year, many of which relapse soon after. In patients over 65, nearly 10% died from the infection.

"Recently, fecal microbiota transplantation has been shown to be effective in the treatment of recurrent C. difficile infection," a study in the New England Journal of Medicine said in 2018. The trials showed FMT worked just as well as antibiotics for treating C. diff.

"This was a small trial, but the results suggest that fecal microbiota transplantation may be an alternative to antibiotic therapy in primary C. difficile infection," the authors wrote.

Read more: uBiome convinced Silicon Valley that testing poop was worth $600 million. Then the FBI came knocking. Here's the inside story.

But following the recent death and sickening of one patient, the FDA is warning more protections and donor screenings are needed to prevent others from contracting infections from MDRO's.

"Patients considering FMT to treat C. difficile infection should speak to their health care provider to understand the potential risks associated with the product's use," the FDA said.