The Internet is a truly revolutionary technology, dramatically altering modern life and enabling multibillion-dollar businesses that would have been inconceivable a few decades ago. Communication, commerce, and entertainment have all been upended by the Internet, a technology that's still in its infancy compared with other major technological breakthroughs.

Despite how much we all depend on the Internet everyday, there are a few things you may not know about this world-changing technology. Three of our Foolish contributors are ready to fill you in on the details.     

Steve Symington (Most of the world doesn't have it): Though access to the Internet is ubiquitous here in the United States, you might be surprised that the World Wide Web is still unavailable to roughly two-thirds of the global population. The reasons are many, from too-expensive Internet-connected devices and a shortage of content in native languages, to a lack of mobile network and power infrastructure in many developing nations.

It should be equally unsurprising, then, that Internet-centric companies such as Facebook (META -0.43%) and Alphabet's (GOOG -1.65%) (GOOGL -1.60%) Google are working hard to bring affordable Internet connectivity to the masses.

Take Facebook's initiative, for example, through which the social-media giant says it's "bringing together technology leaders, nonprofits, and local communities to connect the two-thirds of the world that doesn't have Internet access." Among's current projects are The Connectivity Lab, where among other things it explores new Internet-delivery technologies including high-altitude, long-endurance drones, lasers, and satellites, and Free Basics, a program to provide people in markets where the Internet is less affordable access to basic health, employment, and local information websites without data charges. Free Basics is already available in parts of Africa, Asia, and Latin America:

Or take Google's "Project Loon," which aims to quite literally use a massive network of high-altitude balloons traveling on the edge of space to fill coverage gaps, connect people in rural and remote areas of the world, and even allow for supplemental connectivity in emergency situations when existing infrastructure is disabled. Earlier this year, Google and Fidelity also collectively invested $1 billion for a nearly 10% stake in Elon Musk's SpaceX. According to sources familiar with the situation, the new financing is being used to support SpaceX's goal of providing Internet access through a global network of around 4,000 satellites within five years.

So in the end, while much of the world is still without the connectivity so many of us take for granted, rest assured it won't stay that way for long if some of the world's largest tech titans have anything to do with it.

Andres Cardenal (Adele's new video is already breaking the Internet). Adele released the video for her new single, "Hello," in the early hours of Friday, Oct. 23, and it's already a massive success on Alphabet's YouTube platform. According to the official YouTube blog, the video got as many as 1.6 million views in a single hour, and it averaged 1 million views per hour in the first two days.

Source: YouTube.

YouTube is increasingly becoming a dominant force in the online world. The platform reportedly has over 1 billion users, representing one-third of all people on the Internet, according to the company. It's also becoming a huge business opportunity and an invaluable strategic asset for Alphabet. 

Alphabet is increasingly capitalizing on YouTube via multiple venues. The number of advertisers using YouTube programmatic solutions has nearly doubled in the past year and a half, and it now includes over 80% of all advertisers in Ad Age's top hundred advertisers list. In addition, Alphabet is exploring new alternatives such as the recently announced shopping ads for YouTube, which allow potential customers to shop directly from a video, turning any relevant video into a digital storefront.   

Online video is here to stay and grow in the years ahead, and Alphabet's YouTube platform puts the company in a position of strength to profit from this massive opportunity in the long term.

Tim Green (It's not very secure): That padlock symbol in the address bar of your Web browser may be reassuring, but the Internet is an inherently dangerous place. Last year, the Heartbleed bug shook the very foundations of Web security, exposing around 17% of all secure Web servers to potential attacks. Heartbleed is a bug in a popular implementation of the Transport Layer Security protocol, OpenSSL, which is widely used to secure communications between servers and clients. That padlock symbol denotes that a website uses TLS for security.

The Heartbleed logo.

Heartbleed took advantage of a simple oversight in OpenSSL's code. Servers using TLS can be sent a "Heartbeat Request," which is a message meant to probe whether the connection to the server is still active. This message contains a payload, which is just a string of text, as well as the length of that payload, and on reception the server sends a message with the payload back to the client.

OpenSSL failed to check whether the length specified in the message matched the length of the payload, and the result was that a malformed message with a shorter payload than the specified length would send back random data from the server's active memory. This random block of data could contain sensitive information, such as user passwords or the server's private security key.

With bugs such as Heartbleed threatening the very foundation of Internet security, it's no wonder that the cybersecurity market is booming. Gartner predicts that more than half of organizations will use security services firms, such as FireEye (MNDT), by 2018, with the market for information security expected to reach $101 billion in that year. FireEye, like many cybersecurity companies, has been riding this cybersecurity wave, growing its revenue by 56% in the latest quarter. And as the number of Internet-connected devices continues to rise, security will only become a larger issue.