What Internet is
The most important technological innovation of our generation, the Internet is actually a network of networks. Originally designed by the U.S. Department of Defense so that a communication signal could withstand nuclear war and serve military institutions worldwide, the Internet was first known as the ARPANet, the most robust communication technology. It is a system of linked computer networks, international in scope, that facilitates data transfer and communication services, such as remote login, file transfer (FTP), electronic mail (e-mail), newsgroups, and the World Wide Web. The Internet greatly extends the reach of each connected computer network (see: network effect, IP).
When you see "internet" written with a lowercase "i," it usually refers to a group of local area networks (LANs) that have been connected by means of a common communications protocol. Many internets exist besides the Internet, including many TCP/IP-based networks that are not linked to the Internet (the Defense Data Network is a case in point).
The meaning of Vertical portal
A portal that caters to consumers within a particular industry (sometimes called a "vertical industry"). Vertical portals, also called "vortals," use Internet technology to offer the same kind of personalization tools that portals do. Another kind of vortal caters solely to other businesses rather than to an industry's consumers. The B2C portal gave the B2B industry a model to work from, and now, most business-to-business sites bill themselves as portals. We like to define business-to-business sites as vertical portals because they deliver content and services focused on their particular niche. The term "portal" is getting muddied because although many sites call themselves portals they are, in fact, simply Web sites that use cookie and/or personalization technology (see: personalize).
The two essential components of a vertical portal are that it uses this kind of technology and caters to a specific industry. The two essential components of a regular portal are that it uses this kind of technology and provides a variety of news, media, and services.