The size of the World Wide WebThe Indexed Web contains at least 27.94 billion pages (Thursday, 29 July, 2010).
How is the size of the World Wide Web estimated?The estimated minimal size of the indexed World Wide Web is based on the estimations of the numbers of pages indexed by Google, Bing, Yahoo Search and Ask. From the sum of these estimations, an estimated overlap between these search engines is subtracted. The overlap is an overestimation; hence, the total estimated size of the indexed World Wide Web is an underestimation.Since the overlap is subtracted in sequence, starting from one of the four search engines, several orderings (and total estimations) are possible. We present two total estimates, one starting with Yahoo (YGBA) and one starting with Google (GYBA). The figure reported at the top of the page refers to the YGBA estimation. The size of the index of a search engine is estimated on the basis of a method that combines word frequencies obtained in a large offline text collection (corpus), and search counts returned by the engines. Each day 50 words are sent to all four search engines. The number of webpages found for these words are recorded; with their relative frequencies in the background corpus, multiple extrapolated estimations are made of the size of the engine's index, which are subsequently averaged. The 50 words have been selected evenly across logarithmic frequency intervals (see Zipf's Law). The background corpus contains more than 1 million webpages from DMOZ, and can be considered a representative sample of the World Wide Web. When you know, for example, that the word 'the' is present in 67,61% of all documents within the corpus, you can extrapolate the total size of the engine's index by the document count it reports for 'the'. If Google says that it found 'the' in 14.100.000.000 webpages, an estimated size of the Google's total index would be 23.633.010.000. The overlap between the indices of two search engines is estimated by daily overlap counts of URLs returned in the top-10 by the engines that were returned in a sufficiently large number of random word queries. The words were randomly drawn from the DMOZ background corpus. You can download my paper here containing detailed information about the method (written in Dutch). This work was carried out as a Master thesis project at the Faculty of Arts of Tilburg University), within the ILK Research Group. Note No countings have taken place for the following dates: 7th of July till the 7th of August 2006. 3th of October till the 16th of October 2007 (Only for The Index Web). 19th of January till the 30th of January 2008 (Only for The Dutch Web). 20th of March till the 1th of April 2008. 5th of May till the 14th of May 2010. |
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The author of this website (Maurice de Kunder) has also made the following Dutch websites: Koopzondagen.net - Koopzondag - Kerstmarkt Winkels-nederland.nl - Winkels Schoolvakanties-nederland.nl - Schoolvakanties Feestdagen-nederland.nl - Feestdagen Kalender-365.nl - Kalender Nederland-in-beeld.nl - Foto's en luchtfoto's van Nederland |
