Google Search Engine : Basic Information

GOOGLE SEARCH ENGINE

Google Search

Google is owned by Google, Inc. whose mission statement is to "organize the world's information and make it universally accessible and useful". The largest search engine on the web, Google receives several hundred million queries each day through its various services.

PageRank

Google uses an algorithm called PageRank to rank web pages that match a given search string. The PageRank algorithm computes a recursive figure of merit for web pages, based on the weighted sum of the PageRanks of the pages linking to them. The PageRank thus derives from human-generated links, and correlates well with human concepts of importance. Previous keyword-based methods of ranking search results, used by many search engines that were once more popular than Google, would rank pages by how often the search terms occurred in the page, or how strongly associated the search terms were within each resulting page. In addition to PageRank, Google also uses other secret criteria for determining the ranking of pages on result lists.

Search results

Google not only indexes and caches (X)HTML files but also 13 other file types, which include PDF, Word documents, Excel spreadsheets, Flash SWF, plain text files, among others. Except in the case of text and SWF files, the cached version is a conversion to (X)HTML, allowing those without the corresponding viewer application to read the file.

Users can customize the search engine somewhat. They can set a default language, use "SafeSearch" filtering technology (which is on 'moderate' setting by default), and set the number of results shown on each page. Google has been criticized for placing long-term cookies on users' machines to store these preferences, a tactic which also enables them to track a user's search terms over time. For any query (of which only the 32 first keywords are taken into account), up to the first 1000 results can be shown with a maximum of 100 displayed per page.

Advanced search operators

Google's searches are not limited to reporting back indexed pages corresponding to the search query. A variety of advanced search operators can be used to perform more sophisticated queries. Some examples are included below:

Search parameters

Search parameters or modifiers are included in a search URL to modify search results. Some examples of search parameters include:

Non-Web sources of data

Despite its immense index, there is also a considerable amount of data in databases, which are accessible from websites by means of queries, but not by links. This so-called deep web is minimally covered by Google and contains, for example, catalogs of libraries, official legislative documents of governments, phone books, and more.

Google optimization

Since Google is the most popular search engine, many webmasters have become eager to influence their website's Google rankings. An industry of consultants has arisen to help websites raise their rankings on Google and on other search engines. This field, called search engine optimization, attempts to discern patterns in search engine listings, and then develop a methodology for improving rankings.

As Google's algorithms and results have gained the trust of web users, commercial websites will profit from subverting these results by artificially inflating their rankings. Some search engine optimization firms have attempted to inflate specific Google rankings by various artifices, and thereby draw more searchers to their client's sites. One of Google's main challenges has been to weaken some of these attempts by reducing the ranking of sites known to use them.

Search engine optimization encompasses both "on page" factors (like body copy, title tags, H1 heading tags and image alt attributes) and "Off Page Optimisation" factors (like anchor text and PageRank). The general idea is to affect Google's relevance algorithm by incorporating the keywords being targeted in various places "on page", in particular the title tag and the body copy (note: the higher up in the page, the better its keyword prominence and thus the ranking). Too many occurrences of the keyword, however, cause the page to look suspect to Google's spam checking algorithms.

One "Off Page Optimisation" technique that works particularly well is Google Adwords in which websites link to another site using a particular phrase in the anchor text, in order to give the site a high ranking when the word is searched for.

The Google webmaster guidelines were published for website owners who would like to raise their rankings when using legitimate optimization consultants.

Uses of Google

A corollary use of Google — and other Internet search engines — is that it can help translators to determine the most common way of expressing ideas in the English language (and other languages). This is generally done by doing a 'count' of different variants, thereby establishing which expression is more common. While this approach requires careful judgment, it does improve the ability of non-native translators to use more idiomatically correct English expressions.

Google dance

Google dance refers to the period of time when Google indices are tuned. This will often cause both a fluctuation in index size as well a significant change in a web site's search result position.

Search engine features

Besides the main search engine feature of searching for text, the search engine can be used as a calculator, currency converter, dictionary and many others useful tools.