Yale University Library/Internet Search Engines

Exercise 4: MetaSearch Engines

MetaSearch Engines are search engines of search engines. Each of them searches a variety of different search engines and returns results from all of them, saving you the time of deciding which of the various individual search engines is the best for your current query.

---

What are the major metasearch engines?

As useful as this can be, there are a number of questions to ask when trying to decide if you need to use a meta engine.

• What are the major metasearch engines?
  All4One (http://www.all4one.com)
  Highway 61 (http://www.highway61.com)
  Inso (http://www.wizard.inso.com)
  Metacrawler (http://www.metacrawler.com)
  ProFusion (http://www.designlab.ukans.edu/Profusion.html)
  SavvySearch (http://guaraldi.cs.colostate.edu:2000/form)
  SuperSeek (http:///www.superseek.com/superseek)

• Which search engines are included in the meta-search?
  This varies from four in the All4One to twenty-eight in SavvySearch.

• Will my search run correctly in all the engines?
  Your search statements won't necessarily be the same in each search engine, especially if you're taking advantage of some of the more advanced capabilities in a particular individual search engine. What works in one may not work in all.

• Are the results of the searches combined in one set or presesnted independently?
  All4One returns the results in the four search engines it searches in four frames. Most will return one set of results from all the engines, with the most relevant hits listed first.

---

Now let's look at one of these meta-engines in more detail...

MetaCrawler:

• Searches seven search engines: AltaVista, Lycos, Exite, Yahoo, HotBot, WebCrawler, and Galaxy.
• Returns one set of results from all searches, with duplicates removed.
• Returns the results in the order of presumed relevance. This is computed by summing and averaging the confidence scores returned by each search engine for the same site.

A sample search:

Let's look for a list of electronic discussion lists dealing with Buddhism. Follow along with the images below, which are pictures of the MetaCrawler screens as they would appear in Netscape.

First, we type in keywords for our search.
(buddhism discussion list)

An intermediate screen will inform you of the progress of your search and the results returned by each search engine.

The final result is thirty-two sites:

Notice that if you use a more advanced search statement . . .
(Buddhism or Buddhist) near "discussion list"

. . . the search fails in some search engines where results were returned with the simpler search.

. . . and the overall number of results drops to eleven.

This isn't necessarily bad! These results may be much more relevant than the thirty-two found using a simpler search statement - and they may be different results, not just a subset of the initial thirty-two.

On to Exercise 5: Finding Email Addresses