2. A web search engine is a software system that is designed to
search for information on the World Wide Web. The search
results are generally presented in a line of results often
referred to as search engine results pages (SERPs). The
information may be a mix of web pages, images, and other types
of files. Some search engines also mine data available
in databases or open directories. Unlike web directories, which
are maintained only by human editors, search engines also
maintain real-time information by running an algorithm on
a web crawler.
A web search engine
3. Electronic mail, most commonly referred to as email or e-mail since ca. 1993,is
a method of exchanging digital messages from an author to one or more
recipients. Modern email operates across the Internet or other computer
networks. Some early email systems required that the author and the recipient
both be online at the same time, in common with instant messaging. Today's
email systems are based on a store-and-forward model. Email servers accept,
forward, deliver, and store messages. Neither the users nor their computers
are required to be online simultaneously; they need connect only briefly,
typically to a mail server, for as long as it takes to send or receive messages.
Historically, the term electronic mail was used generically for any
electronic document transmission. For example, several writers in the early
1970s used the term to describe fax document transmission.As a result, it is
difficult to find the first citation for the use of the term with the more specific
meaning it has today.
An Internet email message consists of three components, the
message envelope, the message header, and the message body. The message
header contains control information, including, minimally, an
originator's email address and one or more recipient addresses
E-Mail
4. Usually descriptive information is also added, such as a subject
header field and a message submission date/time stamp.
Originally a text-only (ASCII) communications medium, Internet
email was extended to carry, e.g. text in other character sets,
multi-media content attachments, a process standardized
in RFC 2045 through 2049. Collectively, these RFCs have come to
be called Multipurpose Internet Mail
Extensions (MIME). Subsequent RFC's have proposed standards
for internationalized email addresses using UTF-8.
Electronic mail predates the inception of the Internet and was in
fact a crucial tool in creating it,but the history of modern,
global Internet email services reaches back to the
early ARPANET. Standards for encoding email messages were
proposed as early as 1973 (RFC 561). Conversion from ARPANET
to the Internet in the early 1980s produced the core of the
current services. An email sent in the early 1970s looks quite
similar to a basic text message sent on the Internet today.
5. A social network is a social structure made up of a set of social actors (such as
individuals or organizations) and a set of the dyadic ties between these actors.
The social network perspective provides a set of methods for analyzing the
structure of whole social entities as well as a variety of theories explaining the
patterns observed in these structures.The study of these structures uses social
network analysis to identify local and global patterns, locate influential
entities, and examine network dynamics.
Social networks and the analysis of them is an
inherently interdisciplinary academic field which emerged from social
psychology, sociology, statistics, and graph theory. Georg Simmel authored
early structural theories in sociology emphasizing the dynamics of triads and
"web of group affiliations." Jacob Moreno is credited with developing the
firstsociograms in the 1930s to study interpersonal relationships. These
approaches were mathematically formalized in the 1950s and theories and
methods of social networks became pervasive in the social and behavioral
sciences by the 1980s. Social network analysis is now one of the major paradigms
in contemporary sociology, and is also employed in a number of other social and
formal sciences. Together with other complex networks, it forms part of the
nascent field of network science
Social network
6. Online chat may refer to any kind of communication over the Internet that offers
a real-time transmission of textmessages from sender to receiver. Chat messages
are generally short in order to enable other participants to respond quickly.
Thereby, a feeling similar to a spoken conversation is created, which distinguishes
chatting from other text-based online communication forms such as Internet
forums and email. Online chat may address point-to-point communications as well
as multicast communications from one sender to many receivers and voice and video
chat, or may be a feature of a web conferencing service.
Online chat in a less stringent definition may be primarily any direct text-based or
video-based (webcams), one-on-one chat or one-to-many group chat (formally also
known as synchronous conferencing), using tools such as instant
messengers, Internet Relay Chat (IRC), talkers and possibly MUDs. The
expression online chat comes from the word chat which means "informal
conversation". Online chat includes web-based applications that allow
communication –often directly addressed, but anonymous between users in a multi-
user environment. Web conferencing is a more specific online service, that is often
sold as a service, hosted on a web server controlled by the vendor.
