The World Wide Web

1
The World Wide Web

• CSCE 101 Fall 2008

2
The Internet and the Web

• Internet A worldwide computer network that
  connects hundreds of thousands of smaller
  networks. The mother of all networks.
• World Wide Web The interconnected system of
  servers that support multimedia documents, i.e.
  the multimedia part of the Internet.
• Timeline
• Early 1960s introduction of the network concept
• 1970 ARPANET, scholarly-aimed networks
• 62 computers in 1974
• 500 computers in 1983
• 28,000 computers in 1987
• 1975 Ethernet developed by Robert Metcalf
• 1980 TCP/IP
• 1981 The first computer virus, Elk Croner,
  spread via Apple II floppy disks
• 1989 Web invented by Tim Berners-Lee
• 1990 First Web browser based on HTML developed
  by Berners-Lee
• Early 1990s Andreesen developed the first
  graphical browser (Mosaic)
• 1993 The White House launches its Web site

3
Web Browsers

• Web Browser Software that enables users to view
  Web pages and to jump from one page to another,
  e.g. IE, Mozilla Firefox, Safari, etc.
• Which browser is better? Why?
• Web Site A computer with a domain name
• Web Page A document on the Web that can include
  multimedia data
• Practical Browser Tools
• Status Bar security info, page load progress
• Favorites (bookmarks)
• View ? Source view the code of a Web page
• Tools ? Internet Options ? history, temporary
  Internet files, home page, auto complete,
  security settings, programs, etc.

4
Domain Names

• URL (Uniform Resource Locator) The
  human-friendly address of a Web page
• String of characters that points to a piece of
  information on the Internet
• Syntax protocol//domain name/directory/file,
  e.g. http//www.sc.edu/mjafaril/lab.html
• The domain name includes the domain type and
  sometimes a country extension
• Have you ever mistyped a URL and gone to a
  website you werent expecting?
• ICANN was established to regulate human-friendly
  domain names
• DNS (Domain Name System) A distributed set of
  servers storing domain information in
  hierarchical fashion
• DNS provides the mapping between the IP addresses
  and URLs of Internet sites
• DNS requires static IP addresses
• DNS poisoning
• Domain names must be registered to ensure
  uniqueness, registration fees vary,
  cybersquatting

5
Cookies

• Little text files left on your hard disk by some
  websites you visit
• Cookies are data not programs, they do not
  generate pop-ups or behave like viruses
• Can include your log-in name and browser
  preferences
• Can be convenient
• But they can be used to gather information about
  you and your browsing habits
• Third party cookies used by advertising
  companies to track users across multiple sites
• People share machines
• Cookie theft modification

session-id-time 954242000 amazon.com/ session-id
002-4135256-7625846 amazon.com/ x-main
eKQIfwnxuF7qtmX52x6VWAXh_at_Ih6Uo5H
amazon.com/ ubid-main 077-9263437-9645324
amazon.com/ Sample Amazon.com cookie
6
E-mail

• E-mail Software and Carriers
• Free Web-based e-mail services (e.g. Yahoo Mail)
  or bundled with software (e.g. MS Outlook)
• E-mail Privacy
• How did they find my e-mail address?
• Can anyone read the content of my messages?
• What happens to my deleted e-mail messages?
• What are my rights?
• Can anything be done to enhance e-mail privacy?
• E-mail Security
• Dangers of attachments and HTML graphics
• Useful E-mail Tools Mailing lists, filters
  (rules)

7
Deciphering Spam

• Spam Unsolicited e-mail in the form of
  advertisements or chain letters.
• Waste of storage space, processing power,
  bandwidth, and time
• E-mail address spoofing, disposable e-mail
  addresses or anonymous re-mailers, and zombies
  are techniques used in spamming
• Motives
• Marketing
• Chain letters hoaxes
• Malicious intent
• Theft of confidential information (e.g. phishing)
• Spam Filters
• Pattern-based
• Challenge-based
• Fight back by reporting new spammers to
  www.abuse.net, www.spamhaus.org, or
  www.rahul.net/falk

8
Searching for Information

• Search engine databases are often compiled using
  software programs called spiders
• Spiders crawl through the Web, following links
  from one page to another
• Index the words on that site
• Indexing techniques
• Influencing search results (paid, malicious e.g.
  Google bombs), link rot
• If you publish an embarrassing web page and then
  take it down, is it REALLY gone?
• Guidelines to evaluate Web resources
• Should you trust information you find online?
• Does the information appear on a professional
  site maintained by a professional organization?
• Does the website authority appear to be
  legitimate?
• Is the website objective, complete, and current?

9
Search Engines

• Types of Search Engines
• Human-organized Documents are categorized by
  subject-area experts, smaller databases, more
  accurate search results, e.g. Open Directory,
  About
• Computer-created Software spiders crawl the web
  for documents and categorize pages, larger
  databases, ranking systems, e.g. Google
• Hybrid Combines the two categories above
• Metasearch or clustering Direct queries to
  multiple search engines and cluster results, e.g.
  Copernic, Vivisimo, Mamma
• Topic-specific
• Advanced Search Options
• Searches for various information formats types,
  e.g. image search, scholarly search
• Advanced query operators and wild cards
• ? (e.g. science? means search for the keyword
  science but I am not sure of the spelling)
• (wildcard, e.g. comput searches for keywords
  starting with comput combined with any word
  ending)
• x AND y (both terms must be present)
• x OR y (at least one of the terms must be
  present)

10
More Web Resources

• Wikis
• A Wiki is a website on which authoring and
  editing can be done by anyone at anytime using a
  simple browser.
• Wikipedia, Wikimedia, Wikibooks, Citizendium,
  etc.
• Allow individuals to edit content to facilitate
• Accuracy concerns
• Internet Telephony (VoIP)
• Providers include Vonage, Verizon, Skype, etc.
• Uses the Internet to make phone calls,
  videoconference
• Long-distance calls are either very inexpensive
  or free
• Quality, security, and reliability concerns

11
More Web Resources

• Social Networks
• MySpace, Facebook, Friendster, Orkut, etc.
• What are some features of todays popular social
  networks?
• Anti-social networks?
• Social networks as study groups, Courses 2.0
• Privacy and safety concerns
• Plagiarism in the Internet Age
• In a recent survey, 60 of students revealed that
  they have cheated in the past
• Websites offering course material, e.g.
  coursehero.com, cheathouse.com
• Use of portable electronic devices for cheating
• Services used to combat cheating, e.g.
  turnitin.com

12
More Web Resources

• Instant messaging (IM) and real-time chat (RTC)
  software
• Multi-protocol IM clients
• Web-based IM systems
• Podcasting
• Blogs
• Blogger, Xanga, LiveJournal, etc.
• Microblog, vlog, photoblog, sketchblog, linklog,
  etc.
• Blog search engines
• Blogs and advertising, implications of ad
  blocking software
• Do bloggers have the same rights as journalists?
• Really Simple Syndication (RSS)
• FireAnt, i-Fetch, RSS Captor, etc.
• Built-in Web browser RSS features
• Search download.com for keyword RSS Readers