Activity 4

What are the advantages and disadvantages of using search engines?

The advantage of using search engine, is that it has most of the information you can search for in the internet, and with absence of book it is a great help to get information.
The disadvantage is that you are not sure if the information is accurate and you have to gamble for it.

Compare and contrast individual search engines and search meta search engines.

In individual the information is stored within the site then the meta use multiple search engine in the net.

When is it appropriate to use a search engine?

when looking for information on the internet, and if the information is reliable and accurate by following the reference or if has a author. If you can't find it the book or in the library you have to used the internet.

When is it appropriate to use a search/subject directory?

when you search for a specific information in the internet.

Question 3
•What is an Invisible Web or ‗Deep Web‘?

There are parts of the Internet that search engines simply can't see. The search engine's  robotic "crawlers" either miss or are locked out of these areas on the Internet.  Behind the barriers lie treasure troves of quality information. Collectively this information is called the Invisible Web.  There are many categories of invisible information missed by the popular search engines.


•How do you find an 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.

As part of your web search strategy, spend a little time looking for databases in your field or topic of study or research. The contents of these may not be freely available: libraries and corporations buy the rights for their authorized users to view the contents. If they appear free, it's because you are somehow authorized to search and read the contents (library card holder, company employee, etc.).

•Why are these web pages not available in search engines or subject directories?

Webpages that have been intentionally skipped by search engine crawlers. Webpages that are dynamically assembled from online database content. Password protected webpages. Non-HTML resources like image, audio, animation, and PDF files