The History and Growth of the Internet 

The Internet Defined
The Internet refers to the global information system that is logically linked together by a globally unique address space based on the Internet Protocol (IP) or its subsequent extensions/follow-ons and is able to support communications using the Transmission Control Protocol/Internet Protocol (TCP/IP) suite or its subsequent extensions/follow-ons, and/or other IP-compatible protocols; and provides, uses or makes accessible, either publicly or privately, high level services layered on the communications and related infrastructure described herein. (Source:  The Federal Networking Council, 1995)

The History of the Internet
The history of the Internet began to take root out of a network developed by the Advanced Research Projects Agency (ARPA) to aid in the sharing of information and resources among researchers. The ARPANET, the network that became the basis for the Internet and made operational in 1969, became an essential tool for remote login, file transfer, electronic mail and the sharing of information by interest groups.  Source:  http://web.simmons.edu/~techcomp/cerf.html
 

Source:  http://www.isoc.org/internet/history/brief.shtml 
 

In 1973, the U.S. Defense Advanced Research Projects Agency (DARPA) started a research program called the Internetting project to develop communication protocols which would allow networked computers to communicate transparently across multiple, linked packet networks.  The system of networks which emerged from the research is what is we know as the Internet. The system of protocols which was developed during this project is the TCP/IP Protocol Suite, after the two initial protocols developed: Transmission Control Protocol (TCP) and Internet Protocol (IP). Source:  http://web.simmons.edu/~techcomp/cerf.html
 

Internet Growth
Since its creation in 1983, the Internet has grown exponentially in terms of numbers of networks connected to it. By 1985, 100 networks, both public domain and commercial utilizing TCP/IP protocol suite became available. By 1987, the number had grown to two hundred; in 1989, it exceeded five hundred and by the end of 1991, the Internet had grown to include some 5,000 networks in over 36 countries, serving over 700,000 host computers used by over 4,000,000 people.

Over the years, there has been wave of commercialization of the Internet. Originally, commercial efforts mainly comprised vendors providing the basic networking products, and service providers offering the connectivity and basic Internet services. The Internet has now become almost a "commodity" service, and much of the latest attention has been on the use of this global information infrastructure for support of other commercial services. This has been tremendously accelerated by the widespread and rapid adoption of browsers and the World Wide Web technology, allowing users easy access to information linked throughout the globe. New products developments in technology are readily accessible as downloads that are providing increasingly sophisticated information services on top of the basic Internet data communications.

Traffic and capacity of the public Internet grew at rates of about 100% per year in the early 1990s. There was then a brief period of explosive growth in 1995 and 1996. During those two years, traffic grew by a factor of about 100, which is about 1,000% per year. In 1997, it appeared that traffic growth has slowed down to about 100% per year  and reports, such as U. S. Department of Commerce's The Emerging Digital Economy, which claim 1,000% growth rates for the Internet, appear to be inaccurate today, since they are based on a brief period of anomalously rapid growth a short while ago. Still, even a doubling each year is fantastically fast by the standards of the communications industry.  If traffic on the Internet continues to double each year, data should exceed voice on U. S. long distance networks around the year 2002. Source: http://www.firstmonday.dk/issues/issue3_10/coffman/

Determining the Number of Web Pages
In 1998 NEC Research Institute analyzed the overlap between search engines and estimated a lower bound limit on the size of the "publicly indexable Web" at 320 million pages (see below for more details). The "publicly indexable Web" excluded pages typically not indexed by the major search engines, e.g. pages behind search forms or authorization requirements.  Therefore, this was a conservative estimate. In 2002, the number of web pages have increased significantly and include not only the "surface" Web, but also the "deep" Web.
 

The "Deep" Web vs The "Surface" Web
There are two groups of Web content. The "surface" Web, which everybody knows as the "Web," a group of static, publicly available web pages, which accounts for a relatively small portion of the entire Web. The other group is called the "deep" Web, which consists of specialized Web-accessible database and dynamic web sites, which are not widely known by "average" surfers, even though the information available on the "deep" Web is 400 to 550 times larger than the information on the "surface" Web.

The "deep" Web is content that resides in searchable databases, the results from which can only be discovered by a direct query. Without the directed query, the database does not publish the result. When queried, "deep" Web sites post their results as dynamic Web pages in real-time. Though these dynamic pages have a unique URL address that allows them to be retrieved again later, they are not persistent. Thus, to be discovered, "surface" Web pages must be static and linked to other pages. Traditional search engines cannot "see" or retrieve content in the deep Web, which by definition is dynamic content served up in real time from a database in response to a direct query.

Size of the Web
Public information on the deep Web is currently 400 to 550 times larger than the commonly defined World Wide Web. The "deep" Web, the fastest growing category of new information on the Internet, contains 7,500 terabytes of information, compared to 19 terabytes of information in the "surface" Web. The "deep" Web contains nearly 550 billion individual documents compared to the 2.5 billion individual documents of the "surface" Web that grows at a rate of 7.3 million pages per day. More than an estimated 100,000 "deep" Web sites presently exist. Sixty of the largest deep Web sites collectively contain about 750 terabytes of information – sufficient by themselves to exceed the size of the surface Web by 40 times.  Source: http://www.brightplanet.com/deepcontent/deep_web_faq.asp#Anchor_dwfaq5

Helpful Links

The Deep Web: Surfacing Hidden Value  White Paper

http://www.netsizer.com/  Internet Growth in Real time

Internet/Web Details  Good Source for Data

http://www.pbs.org/internet/timeline/  Cool Time Line

http://www.isoc.org/internet/history/brief.shtml  A Brief History of the Internet

http://www.internettrafficreport.com/  Internet Traffic Report