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How to... use search engines effectively

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Semantic and computational search

Semantic search means that the software does not crawl randomly through its index of web pages searching for the input term, but rather queries the item against its own structured data. In other words, there is some intelligence in the search: information is organized in a structured way, by humans, against the software's metadata.

Such an approach is exemplified by (WA), launched in May 2009. WA describes itself as a "computational knowledge engine" and works differently from standard search engines. It checks every search query against a database of facts which have been compiled by its team, basing its answer on algorithms.

The long-term aim is to make all knowledge computable and accessible to everyone. According to its website,

"Our goal is to build on the achievements of science and other systematizations of knowledge to provide a single source that can be relied on by everyone for definitive answers to factual queries" (Wolfram|Alpha, 2010).

The idea is to save users time in two main ways:

  1. It displays the resulting information cleanly within the interface on the page, so there is no need to click in and out of results pages. Thus while searching "France" in Google would bring up references to Wikipedia, French hotels, etc., an AW search brings up a whole range of facts about the country, including maps, statistics, economic indicators, etc.
  2. It provides answers, not sources of answers. If you want, for example, to convert $30,000 into UK sterling, it will display the answer rather than directing you to currency converting sites, and helpfully also provide a graph showing exchange history.

WA's main drawback is the size of its database: at 10 terabytes last October (Higgins, 2009), it is smaller than Google. According to its website (Wolfram|Alpha, 2010) it holds 10+ trillion pieces of data and 50,000+ types of algorithms and models. There are still significant gaps, however, and WA would be the first to admit that the site has a long way to go.

From a reference librarian's point of view, it is a good place to search for basic facts, for example about a country. It is also particularly strong on scientific and mathematical data.

Figure 1. The Wolfram|Alpha search engine, showing the results of a query for "silver, gold', which provides comparative information for the two elements (© Wolfram|Alpha).

Figure 1. The Wolfram|Alpha search engine, showing the results of a query for "silver, gold', which provides comparative information for the two elements (© Wolfram|Alpha)

While WA undoubtedly leads the way in computational search, it is not alone, particularly with regard to use of underlying factual databases.

Microsoft's Bing was also launched in May 2009, and like WA, claims to be able provide direct answers to questions. Bing finds these answers from two underlying databases that Microsoft took over: one relating to travel and shopping, and the other, the semantic-based Powersearch, which indexes Wikipedia.

Bing describes itself as a "decision engine", helping users make key decisions and providing instant answers. For example, a search "London to Johannesburg" brings up a list of sites providing flight information.

The search engine Ask (Ask Jeeves in Britain) has long relied on a database of questions and answers, and was recently relaunched as a natural language search engine, which can generate results both automatically and based on a human edited database of responses.

And Google, claims Matt Cutts (Skipease, 2009), is becoming increasingly sophisticated and semantically empowered: it can factor in synonyms, phrase structure and user intent.

Not all, however, favour these new database search methods. Pandia Search Engine News points out that there is a flaw in thinking that sites like Wolfram|Alpha and Ask can save time by answering the user's questions. Not all questions have one answer, and information may best be gleaned by going to a number of sources (Pandia, 2010). This is particularly so for very recent information, or where narrative information as in a news story, or subjective information (as in reviews of a hotel) is required.