The Internet is a vast international network comprised of about 150,000 individual networks and tens of millions of individual users around the world. Attempts to quantify the size of the Internet are extremely difficult given that there is no central point of control and because, by all accounts, the medium is growing at a nearly exponential rate.
Specialized computers send each packet onward, selecting the least congested path.
Packets forming a single communication will often follow very different paths, passing through many networks and being routed onward at each location. At the destination, another computer will put the message back together following self-contained instructions. Neither the sender nor the recipient is likely to know nor care what routes the message traveled. ISPs are engaged primarily in the sale of Internet access to business and consumers while OSPs, such as America Online, Compuserve or Prodigy, offer their own proprietary content as well as access to the Internet. The Internet and its most prominent application, the World Wide Web, are by nature global and unmindful of traditional geographical boundaries.