Common Crawl is a nonprofit501(c)(3) organization that crawls the web and freely provides its archives and datasets to the public.[1][2] Common Crawl's web archive consists of petabytes of data collected since 2008.[3] It completes crawls generally every month.[4]
Common Crawl was founded by Gil Elbaz.[5] Advisors to the non-profit include Peter Norvig and Joi Ito.[6] The organization's crawlers respect nofollow and robots.txt policies. Open source code for processing Common Crawl's data set is publicly available.
The Common Crawl dataset includes copyrighted work and is distributed from the US under fair use claims. Researchers in other countries have made use of techniques such as shuffling sentences or referencing the common crawl dataset to work around copyright law in other legal jurisdictions.[7]
As of March 2023, in the most recent version of the Common Crawl dataset, 46% of documents had English as their primary language (followed by German, Russian, Japanese, French, Spanish and Chinese, all below 6%).[8]
History
Amazon Web Services began hosting Common Crawl's archive through its Public Data Sets program in 2012.[9]
The organization began releasing metadata files and the text output of the crawlers alongside .arc files in July 2012.[10] Common Crawl's archives had only included .arc files previously.[10]
In December 2012, blekko donated to Common Crawl search engine metadata blekko had gathered from crawls it conducted from February to October 2012.[11] The donated data helped Common Crawl "improve its crawl while avoiding spam, porn and the influence of excessive SEO."[11]
In 2013, Common Crawl began using the Apache Software Foundation's Nutch webcrawler instead of a custom crawler.[12] Common Crawl switched from using .arc files to .warc files with its November 2013 crawl.[13]
A filtered version of Common Crawl was used to train OpenAI's GPT-3 language model, announced in 2020.[14]
Timeline of Common Crawl data
The following data have been collected from the official Common Crawl Blog[15]
and Common Crawl's API.[16]
Crawl conducted from November 28 to December 12, 2023
June 2023
390
3.1
Crawl conducted from May 27 to June 11, 2023
April 2023
400
3.1
Crawl conducted from March 20 to April 2, 2023
February 2023
400
3.15
Crawl conducted from January 26 to February 9, 2023
December 2022
420
3.35
Crawl conducted from November 26 to December 10, 2022
October 2022
380
3.15
Crawl conducted in September and October 2022
April 2021
320
3.1
November 2018
220
2.6
October 2018
240
3.0
September 2018
220
2.8
August 2018
220
2.65
July 2018
255
3.25
June 2018
235
3.05
May 2018
215
2.75
April 2018
230
3.1
March 2018
250
3.2
February 2018
270
3.4
January 2018
270
3.4
December 2017
240
2.9
November 2017
260
3.2
October 2017
300
3.65
September 2017
250
3.01
August 2017
280
3.28
July 2017
240
2.89
June 2017
260
3.16
May 2017
250
2.96
April 2017
250
2.94
March 2017
250
3.07
February 2017
250
3.08
January 2017
250
3.14
December 2016
—
2.85
October 2016
—
3.25
September 2016
—
1.72
August 2016
—
1.61
July 2016
—
1.73
June 2016
—
1.23
May 2016
—
1.46
April 2016
—
1.33
February 2016
—
1.73
November 2015
151
1.82
September 2015
106
1.32
August 2015
149
1.84
July 2015
145
1.81
June 2015
131
1.67
May 2015
159
2.05
April 2015
168
2.11
March 2015
124
1.64
February 2015
145
1.9
January 2015
139
1.82
December 2014
160
2.08
November 2014
135
1.95
October 2014
254
3.7
September 2014
220
2.8
August 2014
200
2.8
July 2014
266
3.6
April 2014
183
2.6
March 2014
223
2.8
First Nutch crawl
Winter 2013
148
2.3
Crawl conducted from December 4 through December 22, 2013
Summer 2013
?
?
Crawl conducted from May 2013 through June 2013. First WARC crawl
2012
?
?
Crawl conducted from January 2012 through June 2012. Final ARC crawl
2009-2010
?
?
Crawl conducted from July 2009 through September 2010
2008-2009
?
?
Crawl conducted from May 2008 through January 2009
Norvig Web Data Science Award
In corroboration with SURFsara, Common Crawl sponsors the Norvig Web Data Science Award, a competition open to students and researchers in Benelux.[17][18] The award is named for Peter Norvig who also chairs the judging committee for the award.[17]
Colossal Clean Crawled Corpus
Google's version of the Common Crawl is called the Colossal Clean Crawled Corpus, or C4 for short. It was constructed for the training of the T5 language model series in 2019.[19] There are some concern over copyrighted content in the C4.[20]
^Brown, Tom; Mann, Benjamin; Ryder, Nick; Subbiah, Melanie; Kaplan, Jared; Dhariwal, Prafulla; Neelakantan, Arvind; Shyam, Pranav; Sastry, Girish; Askell, Amanda; Agarwal, Sandhini (2020-06-01). "Language Models Are Few-Shot Learners". p. 14. arXiv:2005.14165 [cs.CL]. the majority of our data is derived from raw Common Crawl with only quality-based filtering.