Ch CHAPTER The Internet and the Web Irfan A. Ilyas Week13 – Lecture02-b

Ch 82 Points to cover  Internet  One-to-One  Offline (Ordinary )  Online (Instant ing- Chat)  Group Mailing  Mailing List  News Groups  Chat Groups  Discussion Group Terminology  Spam Mail

Ch 83 Internet  Chat (Instant ing)  Lets the Internet users communicate interactively  Requires a three computer setup  Chat Server  Two Chat Clients Buddy List User1 User2 User3 User1 User2 Chat Server

Ch 84 Chat Mechanism Details  Server Computer  Chat server saves a list of registered users name.  Lets client computers login into the server.  Marks the name of the clients (with a different color) who are currently logged-in  Sends a selected list of client names to every logged-in client  Client Computer  User on a client computer uses a chat client software  To get registered on the chat server  To login to the server  User can select the user names for their buddys (friends)  Chat client will be receiving a list of these selected users (with their current status) whenever logged in. A logged in chat user can initiate an instant (chat) session with any other logged in user through the chat server.

Ch 85 Group ing  Mail Lists  A group of people ( addresses) are attached to a single group address (list address)  Any message sent to the list address will be copied and automatically sent to all members  List Management  Mail list management software are responsible for  List address creation  Linking users to a list address (subscribing)  Removing users from a list address (unsubscribing)  Mostly, such a software is working either  Through a web page link (for subscribe/ unsubscribe) OR  Sending s to an automated manager (with the subject subscribe or unsubscribe)

Ch 86 …Mail Lists  How to subscribe/ unsubscribe a mailing list?  Through a web page  By sending “subscription request”

Ch 87 …Mail Lists  Mail List Archive Searching  Using a Mailing List without initiating a new discussion  Mailing List archive searching allows members/ non- members to search for their interested topic (discussed in the past)

Ch 88 Popular Mailing List Addresses

Ch 89 Group Mailing  News Groups  Another mechanism of having a group discussion  A newsgroup server computer acts like an electronic bulletin board space  A number of topics for discussion are available (new ones can also be initiated)  A separate network of newsgroup server computers is managing a huge newsgroup setup, called USENET.

Ch News Groups  Details of USENET  USENET exists even before Internet (started in 1979 by Duke University & University of N. Carolina Graduates)  Over 10,000 different newsgroups organized into major topic areas (further subdivided into subtopics)  Mechanism  All computers (news group servers) offer a bunch of news groups for discussion  Whenever a message is posted to one of these computers, it will eventually be copied (automatically) to all USENET computers. Comp windows …. News …. rec arts movies ….. sci talk soc rec.arts.movies

Ch 811 …Newsgroups  How to connect a newsgroup computer?  Some of the USENET newsgroups are also have a connection with the Internet  These computers can be contacted by Internet users through their Internet Address.  The user needs a newsgroup reader program (Microsoft Outlook Express can be used) New York Log Angeles Washington North Carolina

Ch 812 …Newsgroups  Newsgroup Servers at KFUPM  Two different newsgroup servers are working internally (not for public Internet)  KFUPM Information Tech. Center (ITC) is maintaining a newsgroup server (news.itc.kfupm.edu.sa) for KFUPM Communities (student, faculty, staff). For details, visit  College of Computer Sci. & Engineering (CCSE) newsgroup server ( news.ccse.kfupm.edu.sa). For details, visit ups/news_groups.html ups/news_groups.html ups/news_groups.html

Ch Newsgroup Servers at KFUPM  Steps in setting up a newsgroup client (Microsoft Outlook Express)  Create a news account ( Tools/ Accounts/ New/ News )  Subscribe to the newsgroups needed

Ch Newsgroup Servers at KFUPM  Download newsgroup message list  Start reading messages  Press Synchronize in order to make the bring the recent messages

Ch 815 Discussion Group Terms

Ch 816 Group Mailing  Group Chats  Allow multiple users to do interactive discussions  Many discussion topics are available  Topics exist on ad-hoc basis (come & go)  A popular group chart service for Internet users, is IRC (Internet Relay Chat)  Users need to have an address of an IRC server computer  IRC Client software is available for free  Very similar to a one-to-one chat in terms of usage (results in chat conferences)

Ch 817 Spam Mail  Unwanted mail/ Junk mail  Being used by marketing departments sending advertisements etc. to as many as possible  ‘address thieves’ are selling addresses to such companies.  Legislation has been approved for penalties etc.

Ch 818 Points to cover  Introducing Web Search Engines  Web Search Index (directories)  Web Search Engines  Web Meta Search Engines

Ch 819 Introducing Web Search Tools  Early 80’s Web was manageable with simple Surfing (exploring web sites through hyperlink clicks)  Information explosion on the Web makes Surfing nearly a “time wastage activity”  Web Search Tools are meant for overcoming the challenge of “finding relevant information” on today’s huge Web

Ch 820 … Introducing Web Search Tools  Types of Search Tools available on the Net  Web Search Index (Starting Point Page)  Web Search Engines  Web Meta Search Engines

Ch Web Search Index  A web search index is a collection of a large number of useful web site addresses  The address collection is presented in an organized fashion  A subject tree is maintained  Sub-topics are maintained under each subject  Collection of web addresses are provided at the lowest level of this tree.

Ch 822 …A Web Search through Yahoo Web Index List of Web Addresses Under Computers and Internet > Magazines > ECommerce Computers and Internet

Ch 823 … Web Search Index  Helps the user to find general information on a subject area.  Examples:  Finding links for popular computer magazines  Finding pages discussing food recipes  Main problems with Web Search Index  Very small fraction of web addresses can be covered (limited scope)  Needs an exhaustive effort to keep the index up-to- date (web explosion rate is exponential)  Not very good for finding specific information

Ch 824 …Details of Yahoo Search Index  Index Administration  Works upon a distributive model  Allows all Internet users to suggest different sites for inclusion into Yahoo! site Index  In order to create a fair and intuitive Index that is of use to everyone  Yahoo!'s subject editors (people qualified in subject categorization/ identification) will review the site  The site may or may not be accepted depending upon its usability  If the site is acceptable, a specific sub-category is assigned to the site  The site address is then included into the index tree  Yahoo Express Program Yahoo Express Program Yahoo Express Program

Ch 825 …Web Search Index  How to choose a good Search Index?  Understanding Limitations  How many sites?  What type of sites (http, gopher, usenet etc.) can be accessed?

Ch Web Search Engines  Search Engines evolved in order to overcome the challenge of Search Index administration  A search engine uses a huge database of web addresses, not- categorized to any subject  Search engine is using a special automated program, called spider (wanderers or worms)  A Spider is capable of:  Automatically discovering web site addresses  Visits these addresses silently and reading HTML documents  updating the database with new (emerging) web document URL with details of there contents (word counts for different words)  A search engine allows the user:  to search for specific words (key words) relevant to their interested topics on all the saved web URLs

Ch 827 … 2. Web Search Engines  Search engine programs are normally accessible through Web addresses  Most search engines also provide a search index list of web addresses  Examples:  Yahoo Search Engine (  Lycos Search Engine (  Drawbacks of Search Engines  Poor precision of the searched document list  Poor searching approach  Varied document quality  Server overload  Use of complex keyword formulas  making use of AND/ OR/ NOT operators for making a detailed search

Ch 828 Comparing Popular Search Engines

Ch 829 Adding your site to a Search Engine  How to include your site into a search engine database?  No need of manual inclusion  Automated spider programs will visit emerging sites and include their URLs into their database

Ch Meta Search Engines  Special search engine service which utilizes multiple search engine databases  A meta searcher doesn’t have its own URL database.  Takes user search request and submit it to multiple search engines for searching  Needs some work in compiling the retrieved URL list  Remove duplicate searches  Sort the list according to the document relevance  integrate results well,  eliminate duplicates,  offer additional features such as intelligent ranking or clustering by subjects within the search results  More Info About Meta Search Engines:

Ch 831 Search List from a Meta Search Engines Name of the Search Engine

Ch 832 Example Meta Searcher Sites Meta Crawler CNet’s Search.com Highway 16 A collection of many meta searchers /corporate/about.htm /corporate/about.htm metacrawlers.html metacrawlers.html

Ch 833