We talked about the differences between a search engine and a directory. Read the Wikipedia pages to get a better understanding of the two. Here is the Wikipedia definition of a (web) directory:
A web directory is a directory on the World Wide Web. It specializes in linking to other web sites and categorizing those links.
A web directory is not a search engine, and does not display lists of web pages based on keywords, instead it lists web sites by category and subcategory. The categorization is usually based on the whole web site, rather than one page or a set of keywords, and sites are often limited to inclusion in only one or two categories. Web directories often allow site owners to directly submit their site for inclusion, and have editors review submissions for fitness.
Here is the definition of a search engine:
A search engine is an information retrieval system designed to help find information stored on a computer system, such as on the World Wide Web, inside a corporate or proprietary network, or in a personal computer. The search engine allows one to ask for content meeting specific criteria (typically those containing a given word or phrase) and retrieves a list of items that match those criteria. This list is often sorted with respect to some measure of relevance of the results. Search engines use regularly updated indexes to operate quickly and efficiently.Directories were made long before search engines, in the mid-1990s. Directories are like lists, and are organized and edited by humans! Yahoo is an example of a directory. The history of Yahoo!:
The two founders of Yahoo!, David Filo and Jerry Yang, Ph.D. candidates in Electrical Engineering at Stanford University, started their guide in a campus trailer in February 1994 as a way to keep track of their personal interests on the Internet. Before long they were spending more time on their home-brewed lists of favourite links than on their doctoral dissertations. Eventually, Jerry and David's lists became too long and unwieldy, and they broke them out into categories. When the categories became too full, they developed subcategories ... and the core concept behind Yahoo! was born.Search engines use spiders, bots, or webcrawlers to visit web sites and record information about what was there in an index. Some famous search engines are Google, Altavista, Ask.com, and others.
Google is relatively new. Although it is a search engine with a very effective indexing technique, Google also has a directory. We visited How Stuff Works to briefly see a description there.
Google is a search engine made by 2 other students at Stanford University who developed a technique called PageRank:
PageRank was developed at Stanford University by Larry Page (hence the name Page-Rank[1]) and later Sergey Brin as part of a research project about a new kind of search engine. The project started in 1995 and led to a functional prototype, named Google, in 1998. Shortly after, Page and Brin founded Google Inc., the company behind the Google search engine. While just one of many factors which determine the ranking of Google search results, PageRank continues to provide the basis for all of Google's web search tools.[2]Dogpile , Surfwax, and Metacrawler are meta-search engines, which search other directories and search engines.
You can find a good explanation of when to use a search engine, and when to use a directory, at this tutorial or this FAQ. This is good advice on searching from Rice University.
We talked about how to use a directory to find reference material, for example, newspapers from various countries, movie screenplays, and song lyrics. We talked about using the Yahoo! directory to find dictionaries, such as OneLook, encyclopedias such as the Wikipedia, and so on.
For searching news, a search engine is probably better, since you can search for keywords and search only news sources at Google News.
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