Blog 2: The Search Engines

Search engines provide some popular ways of finding information on the intenet. There is a wide variety of search engines and features. Some search engines are on specific websites, allowing visitors to the site to search for specific words or phrases. Others are broader in scope.

Advantage of using search engines


Basically their are more of advantages and less of disadvantages the advantages include the results come fast and are very quick, your time is saved a lot and the disadvantage are you get totally dependent upon the internet for your searches.

Advantages -
you get what you need easily.
easy, quick access to information

Disadvantages -
you get even what you shouldn't get
you get lazy and depend on the Internet

Advantages:


Variety

1. An Internet search can generate a variety of sources for information. Results from online encyclopedias, news stories, university studies, discussion boards, and even personal blogs can come up in a basic Internet search. This variety allows anyone searching for information to choose the types of sources they would like to use, or to use a variety of sources to gain a greater understanding of a subject.

Precision

2. Search engines do have the ability to provide refined or more precise results. Putting quotations marks around a set of words will bring up results with the exact same words, excluding others. Some search engines, such as Google or Yahoo, enable you to specify the type of web sources to be searched. Being able to search more precisely allows you to cut down on the amount of information generated by your search.
   
   Search engines within a website allow you to search information only on that website, filtering out information from other web sources and giving more precision in a user's search for information.

Organization

3. Internet search engines help to organize the Internet and individual websites. Search engines aid in organizing the vast amount of information that can sometimes be scattered in various places on the same web page into an organized list that can be used more easily.

Read more: The Advantages of Using Search Engines | eHow.com http://www.ehow.com/list_6120742_advantages-using-search-engines.html#ixzz0yvyvKvWE


Comparison and Contrast of search engines and meta search engines

Though there are dozens of useful meta search engines, InfoSpace is the industry gorilla, operating the four arguably best known and most heavily used properties.

Dogpile and Metacrawler are the two best known InfoSpace meta search engines. Less well known is that InfoSpace purchased the Excite and Webcrawler properties when Excite failed, and quietly re-engineered their back ends as meta search engines.

A key component of InfoSpace's new focus is still "monetization," but the company has also refocused on two other core goals: To improve quality of results and to improve the performance of the search engines.

As part of this process, InfoSpace has cut deals with Fast, Google and Inktomi to include results from their sites in addition to the paid listings provided by Overture, FindWhat, Ah-Ha, and other results from LookSmart, About, Ask Jeeves, SearchHippo, the Open Directory Project, and InfoSpace's own directories.

Query analysis has also been improved. The engines first try to determine whether the user is looking for commercial or non-commercial results, according to Tasha Irvine, InfoSpace product unit manager, search.

When to Use Search Engine Databases:

Search engines are the best tools to use when you are looking for very specific information or when your research topic has many facets. Usually when you need information on a very detailed or multifaceted subject, a search engine will give you not only more information, but also the most precise and up-to- date information possible. Even though most of the major search engine databases attempt to index the entire Web, each one has a different way of determining which pages are most relevant to your search request. In one database, a relevant document may be fiftieth on the list; in another database, that document may be first. In order to retrieve the most relevant documents, you should become familiar with many search engines and their features.

Invisible Web. Traditionally refers to the information available through eways or search interfaces that is not accessible by the search engines’ robots. It is a huge part of the Internet content, including library catalogues, bibliographic and alphanumeric databases or even some repositories of documents. During last years some engines, specially Google, has made a great effort to index these records and in fact several databases are more or less covered in their systems (i.e. PubMed is partially indexed by Google). Our ranking do not consider the Invisible or Deep Web and we encourage transforming it in crawler friendly information.

How to Find the Invisible Web

Simply think "databases" and keep your eyes open. You can find searchable databases containing invisible web pages in the course of routine searching in most general web directories. Of particular value in academic research are:

• ipl2
• Infomine

Use Google and other search engines to locate searchable databases by searching a subject term and the word "database". If the database uses the word database in its own pages, you are likely to find it in Google. The word "database" is also useful in searching a topic in the Google Directory or the Yahoo! directory, because they sometimes use the term to describe searchable databases in their listings.

Examples:

plane crash database

languages database

toxic chemicals database

Remember that the Invisible Web exists. In addition to what you find in search engine results (including Google Scholar) and most web directories, there are other gold mines you have to search directly. This includes all of the licensed article, magazine, reference, news archives, and other research resources that libraries and some industries buy for those authorized to use them.

Why isn't everything visible?

There are still some hurdles search engine crawlers cannot leap. Here are some examples of material that remains hidden from general search engines:

• The Contents of Searchable Databases. When you search in a library catalog, article database, statistical database, etc., the results are generated "on the fly" in answer to your search. Because the crawler programs cannot type or think, they cannot enter passwords on a login screen or keywords in a search box. Thus, these databases must be searched separately.
  
  
  • A special case: Google Scholar is part of the public or visible web. It contains citations to journal articles and other publications, with links to publishers or other sources where one can try to access the full text of the items. This is convenient, but results in Google Scholar are only a small fraction of all the scholarly publications that exist online. Much more - including most of the full text - is available through article databases that are part of the invisible web. The UC Berkeley Library subscribes to over 200 of these, accessible to our students, faculty, staff, and on-campus visitors through our Find Articles page.


• Excluded Pages. Search engine companies exclude some types of pages by policy, to avoid cluttering their databases with unwanted content.
  
  
  • Dynamically generated pages of little value beyond single use. Think of the billions of possible web pages generated by searches for books in library catalogs, public-record databases, etc. Each of these is created in response to a specific need. Search engines do not want all these pages in their web databases, since they generally are not of broad interest.
  
  
  • Pages deliberately excluded by their owners. A web page creator who does not want his/her page showing up in search engines can insert special "meta tags" that will not display on the screen, but will cause most search engines' crawlers to avoid the page.

source: http://library.berkeley.edu/TeachingLib/Guides/Internet/InvisibleWeb.html