Arpanet carried its first message on October 29, 1969, laying the foundation for today\u2019s networked world. Fifty years later, more than 4 billion people have internet access, and the number of devices connected to IP networks is more than double the global population. Here\u2019s a look at some key milestones in the history of the internet and\u00a0 projections for its future growth.\nArpanet, precursor to the internet\nThe name Arpanet came from the U.S. military arm that funded it, the Advanced Research Projects Agency. When Arpanet was created, it connected five sites: UCLA, Stanford, UC Santa Barbara, the University of Utah and BBN Technologies.\n\nLearn more\n\n7 steps to enhance IoT security\nSD-WAN: What is it and why you\u2019ll use it one day\nWhat is 5G? How is it better than 4G?\nMaking the right hyperconvergence choice: HCI hardware or software?\n\n\nThe first Arpanet node was set up at UCLA on Aug. 30, 1969. The second node, at the Stanford Research Institute, was set up on Oct. 1. The first data message sent between the two networked computers occurred on Oct. 29, when UCLA computer science professor Leonard Kleinrock sent a message from his school's host computer to another computer at Stanford. Kleinrock intended to write "login" to start up a remote time-sharing system, but the system crashed after only two letters, "l" and "o", were transmitted.\nIn 1983, the U.S. Defense Department spun-off MILNET, which was the part of Arpanet that carried unclassified military communications. (MILNET was later renamed the Defense Data Network and finally NIPRNET, for Non-classified IP Router Network.) Arpanet was renamed the internet in 1984, when it linked 1,000 hosts at university and corporate labs.\nToday, there are 4.4 billion Internet users worldwide, according to Internet World Stats. Globally, the internet has changed from a U.S.-dominated communications medium to one that has penetrated more than half of the world\u2019s 7.7 billion population.\nWorld Wide Web turns 30 years old\nIn 1989, Tim Berners-Lee wrote a paper that\u00a0laid out his thoughts\u00a0for a method of publishing information in a hypertext format on the Internet. His vision of universal connectivity became the World Wide Web, which sent internet usage skyrocketing. In 1993, computer science student Marc Andreessen created the first popular web browser, known as Mosaic. Today, there are more than 1.7 billion web sites (of these, less than 200 million are active), according to Internet Live Stats. The milestone of 1 billion web sites was first reached in September of 2014.\nMoving from IPv4 to IPv6\nThe Internet Protocol identifies devices across the internet so they can be located. IPv4, the first major version, was invented in the 1970s and introduced to the public in 1981. Twenty years ago, the Internet Engineering Task Force (IETF) started predicting the depletion of IPv4 addresses and began working to create a new version of the Internet Protocol: IPv6.\nIPv4 uses a 32-bit addressing scheme to support 4.3 billion devices; IPv6 uses 128-bit addressing to support approximately 340 trillion trillion trillion devices. A dwindling supply of IPv4 addresses led to the Internet Assigned Numbers Authority \u2013 the global overseers of network addresses \u2013 reporting in 2011 that it had run out of new addresses to dish out to regional internet registries (RIR). A few years later, in 2015, the American Registry for Internet Numbers (ARIN) reported depleting its free pool of IPv4 addresses.\nStill, the transition to IPv6 has been slow. Carrier networks and ISPs were among the first groups to start deploying IPv6 on their networks. Today, T-Mobile USA has 94% of its traffic going over IPv6, for example, while Verizon Wireless is at 85%, and AT&T Wireless is at 76%, according to the industry group World Ipv6 Launch. Enterprises have trailed in deployment, citing cost, complexity and resource challenges. According to Google, IPv6 connectivity around the world is at roughly 25% today; IPv6 adoption in the U.S. is nearly 38%.\nDNS, the internet\u2019s phonebook\nThe Internet's Domain Name System (DNS) was created in 1984 to match complex IP addresses with easy-to-remember names ending in extensions such as .com, .org, .edu, .gov and .mil. The first dot-com domain names were registered in 1985, beginning with Symbolics.com, BBN.com, Think.com, MCC.com, DEC.com and Northrop.com. In 1998, the U.S. Department of Commerce privatized domain-name registrations and operations through the creation of the Internet Corporation for Assigned Names and Numbers (ICANN).\nDomain name sales continue to climb \u2013 the first quarter of 2019 closed with 351.8 million domain name registrations across all top-level domains \u2013 along with the number of threats to DNS security. DNS threats include DNS hijacking, tunneling, phishing, cache poisoning and DDoS attacks. In 2019, IDC reported that 82% of companies worldwide have faced a DNS attack over the past year, and in the U.S., the average cost of a DNS attack tops out at more than $1.27 million.\nInternet traffic heading for 5 zettabytes per year\nDaily traffic on the Internet surpassed 3 million packets in 1974. First measured in terabytes and petabytes, monthly traffic volume is now measured in exabytes, which is\n1018 bytes. In 2017, the annual run rate for global IP traffic was 122 exabytes per month, or 1.5 zettabytes per year, according to Cisco\u2019s Visual Networking Index. Annual global IP traffic will reach 396 exabytes per month, or 4.8 zettabytes per year, by 2022, Cisco predicts.\nAs traffic volume has grown, so too has the number of devices connected to the internet. Today, the number of devices connected to IP networks is approaching 20 billion. By 2022, there will be 28.5 billion networked devices, up from 18 billion in 2017, Cisco predicts. That\u2019s more than the number of people in the world. Overall, Cisco predicts there will be 3.6 networked devices per person by 2022, up from 2.4 in 2017.\nSmartphones overtake PCs\u00a0\nToday, smartphone traffic continues to grow and is poised to exceed PC traffic in the coming years. In 2018, PCs accounted for 41% of total IP traffic, but by 2022 PCs will account for only 19 percent of IP traffic, according to Cisco\u2019s data. Smartphones will account for 44 percent of total IP traffic by 2022, up from 18% in 2017.\nM2M and IoT take hold\u00a0\nThe number of devices and connections is growing faster than the global population, and the fastest-growing category is machine-to-machine (M2M) connections, according to Cisco's research. M2M applications include smart meters, video surveillance, healthcare monitoring, transportation, and package or asset tracking; it's a subset of the larger internet of things (IoT) movement. The IoT is a network of smart devices, such as sensors, machines and cameras, that can autonomously connect to the internet and share information, driving enormous network traffic and generating zettabytes of data for monitoring and analysis. Research firm IDC estimates there will be 41.6 billion connected IoT devices generating 79.4 zettabytes of data in 2025.\nInternet security threats\nBack in 1988, the Morris Worm disabled 10% of the internet's 60,000 host computers. Considered the first major attack on the internet, the Morris worm served as a wake-up call to the internet engineering community about the risk of software bugs.\nThreats have continued to pile on since then. Memorable attacks include Mafiaboy, a massive distributed denial-of-service attack traced to a Montreal-area teen calling himself Mafiaboy. The attack felled Amazon, eBay, Yahoo, Dell, E-trade and CNN on Feb. 7, 2000. The same year, the ILoveYou worm (also called VBS\/Loveletter and the Love Bug Worm) infected an estimated 10% of all connected computers.\nToday, attacks against Internet-connected systems are too numerous to count. The financial consequences for companies that are victimized are significant: Globally, the cost of a data breach has risen 12 percent over the past five years and now costs $3.92 million on average, according to IBM Security.\u00a0\nSocial media calling\nWhen Pew Research Center began tracking social media adoption in 2005, just 5% of American adults used at least one social media platform. Usage reached 50% of all Americans by 2011, and today 72% of the public uses some type of social media.\nEvery second, on average, around 6,000 tweets are published. More than 500 million tweets are sent every day, and roughly 200 billion tweets are sent per year, according to Internet Live Stats. More than 4 million blog posts are published on the Internet every day. There are 1.59 billion daily active users on Facebook, as of June 2019. In addition, more than 2.1 billion people use Facebook, Instagram, WhatsApp, or Messenger every day on average, Facebook reports.\nSearch and shop\nMore than 5 billion Google searches are made every day, industry watchers estimate. E-commerce continues to thrive. Since the mid-1990s, e-commerce sales have climbed steadily and represented an increasing share of the total retail market. In 2018, consumers spent $517 billion online with U.S. merchants, taking a 14 percent share of total retail sales.