The Internet is a worldwide system of computer networks that allows users to access information from any other connected computer. It was originally conceived by ARPA in 1969 to allow researchers to share information. Electronic mail (email) allows Internet users to send messages to each other, containing text, images, audio or video. File Transfer Protocol (FTP) enables users to transfer files between computers on the Internet by downloading files from remote computers or uploading files to them. Telnet allows users to log into other computers remotely. Usenet allows groups of users to exchange views on topics of common interest through newsgroups. The World Wide Web (WWW) uses hypertext and links to organize and access vast amounts of information through web pages, which are created

1. Internet
The Internet, sometimes called simply "the Net," is a worldwide system of computer
networks - a network of networks in which users at any one computer can, if they
have permission, get information from any other computer (and sometimes talk
directly to users at other computers). It was conceived by the Advanced Research
Projects Agency (ARPA) of the U.S. government in 1969 and was first known as the
ARPANet. The original aim was to create a network that would allow users of a
research computer at one university to "talk to" research computers at other
universities.
Electronic Mail
Electronic mail service (known as e-mail in short) enables an internet user to send a
mail (message) to another internet user in any part of the world. An e-mail takes a
few seconds to several minutes to reach its destination, because it travels from one
network to another, until it reaches its destination. Messages in a e-mail service can
contain not only text documents but also image, audio and video data. Only
restriction is that the data must be in computer-readable format.
E-mail service has many similarities with postal service
 All internet users have e-mail address, just as all of us have a postal address.
 Each internet user has a logical mailbox, just as each one of us has a mailbox
in our house.
 When sending a mail to another user, a sender specifies the e-mail address of
the receiver, just as we write postal address of the receiver of a post in postal
mail system.
A compared to paper mail, telephone and fax many prefer e-mail because of its
following advantages:
 It is faster than paper mail.
 Unlike telephone, the persons communicating need not to be available at the
same time.
 Unlike fax document, the receiver of an e-mail document can store it in a
computer, can edit it easily using editing programs.

2. File Transfer Protocol (FTP)
FTP service enables an internet user to move a file from one computer to another on
the internet. A file may contain any type of digital information- text document,
image, artwork, movie, sound, software etc.
Downloading is the process of moving a file from a remote computer to one’s own
computer
Uploading is the process of moving a file from one’s own computer to a remote
computer.
Notice that a user need access rights for a remote computer to transfer files from/to
it. With this restriction, it is impossible to provide access rights to the large number
of users on the internet to a computer that contain sharable information.
Telnet
Telnet service enables an internet user to log in to another computer on the internet
from his/her local computer. That is, a user can execute the telnet command on
his/her local computer to start a login session on a remote computer. This action is
also called remote login.
Usenet News
Usenet service enable a group of internet users to exchange their
views/ideas/information on some common topic of interest with all member
belonging to the group. Several such groups exists on the internet and are called
newsgroups. For example, a newsgroup named comp.security.misc consists of users
having interest in computer security issues.
World Wide Web (WWW)
The World Wide Web ( called WWW or W3 in short) is the most popular and
promising method of organizing and accessing information on the internet. Main
reason for its popularity is use a concept called hypertext.
Hypertext is a new way of information storage and retrieval that enables authors to
structure information in novel ways. A properly designed hypertext document can
help users locate desired type of information rapidly from vast amount of
information on the internet. Hypertext documents enable this by using a series of
links.

3. A link is a special type of item in a hypertext document connecting the document to
another document that provides more information about the linked item.
Hypertext documents on the internet are known as web pages. Web page designer
create web page by using a special language called Hypertext Markup Language
(HTML).
WWW Browsers
To use a computer as a wed client, a user needs to load on it a special software tool
known as WWW browser (or browser in short).
Internet Search Engine
An internet search engine is an application, which helps users locate web sites
containing useful information and references to such information on the WWW. To
search information on the WWW, a user types the description of the information
using the user interface of the search engine. The search engine then searches the
requested information on the WWW and returns the results to the user.
Some Popular Internet Search Engines
1. HotBot (www.hotbot.com)
2. Yahoo (www.yahoo.com)
3. Lycos (www.lycos.com)
4. Infoseek (www.infoseek.com)
5. Google (www.google.com)
6. Inference Find (www.infind.com)
7. Ixquick (www.ixquick.com)
Uses of the Internet
 On-line communication
 Software sharing
 Exchange of views on topics of common interest
 Posting of information of general interest
 Organization promotion
 Product promotion and feedback about products
 Customer support service
 On-line journals, magazine and dictionary
 On-line shopping

4.  Worldwide video conferencing
 Worldwide web casting