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Industry Crowdsourcing
Founded December 2007 (2007-12)
Founder Lukas Biewald
Chris Van Pelt
Headquarters San Francisco, California, United States
Owner Lukas Biewald
Number of employees

CrowdFlower is a data enrichment, data mining and crowdsourcing company based in the Mission District of San Francisco, California. The company's software as a service platform allows users to access an online workforce of millions of people to clean, label and enrich data. CrowdFlower is typically used by data scientists at academic institutions, start-ups and large enterprises.


CrowdFlower was founded in 2007 by Lukas Biewald and Chris Van Pelt, as "Dolores Labs." CrowdFlower received $1,200,000 in seed funding in March 2009 from K9 Ventures, Quest Venture Partners, Gary Kremen, FF Angel, and Uber CEO Travis Kalanick, among others.[1] In January 2010, CrowdFlower raised a $5,000,000 Series A that included Bessemer Venture Partners, Trinity Ventures, and Founders Fund.[2] In March 2011, CrowdFlower raised a $9,300,000 Series B followed by a $12,500,000 Series C in September 2014,[3] this time led by Canvas Venture Fund.[4] In October 2014 the company laid off half of it's staff due to "growth problems in the platform."


CrowdFlower cleans up messy and incomplete data using an online workforce of millions of people. Typical users of CrowdFlower are data scientists who utilize the software to create training data to build models and train machine learning algorithms.

The platform allows users to distribute work to contributors in the U.S. and 153 other countries while maintaining quality and controlling costs. On a continuous basis, these contributors discover work on online job boards and decide what they're going to work on based on how interesting it is, how much work is available and how much the job compensates them. These jobs can include analyzing the sentiment of tweets on a brand or hashtag, scoring relevance for search queries and results of an e-commerce website or moderating user generated content.

Once data is uploaded to the platform, the system automatically allocates the work to contributors and tests them against known answers hidden within the task (what CrowdFlower refers to as a "job" [5]). The way in which contributors perform on these hidden test questions calibrates how much the system trusts them on an individual level. As long as contributors remain trusted they're allowed to continue working on a given job. If they become untrusted, they're removed from the job and all of their work is disregarded. Multiple contributor judgments are collected and an aggregate answer with an associated confidence score (agreement of the contributors weighted by the trust of each contributor) is provided as a result - effectively returning the "most trusted judgment," for a given unit of data.


CrowdFlower's community is a diverse and expansive network of contributors who complete simple online tasks distributed by the platform. Contributors from 208 countries and territories have completed more than 1.5 billion judgements for the platform customers.


  • Researchers at the Harvard Tuberculosis Lab used it to identify drug-resistant TB cells.[6]
  • After the 2010 Haiti earthquake, the company helped to route text messages to the proper aid workers, to get them translated, and to ensure that the people sending the texts had a chance of getting what they needed.[7]
  • Similar relief efforts were handled after the 2010 Pakistan floods.[8]
  • In 2009, the company worked with Samasource to provide work for refugees in Kenya who completed microtasks; iPhone users donated their time by checking for accuracy through Give Work, an app.[9]

See also[edit]


  1. ^ [1] Archived October 3, 2014, at the Wayback Machine.
  2. ^ [2] Archived September 23, 2014, at the Wayback Machine.
  3. ^ Derrick Harris. "CrowdFlower raises $12.5M to deliver better data for better models". 
  4. ^ [3] Archived October 29, 2014, at the Wayback Machine.
  5. ^ Archived from the original on August 12, 2014. Retrieved October 7, 2014.  Missing or empty |title= (help)
  6. ^ Adrienne Burke (2011-10-26). "Crowdsourcing Scientific Progress: How Crowdflower's Hordes Help Harvard Researchers Study TB". Forbes. Retrieved 2012-01-31. 
  7. ^ "Crowdsourcing the Haiti Relief | The CrowdFlower Blog". 2010-01-29. Retrieved 2012-01-31. 
  8. ^ "How To Cope with Very Large Volumes of Crowdsourced Reports? Add More Crowd!". The Ushahidi Blog. Retrieved 2012-01-31. 
  9. ^ Oshiro, Dana (2009-10-13). "Samasource / CrowdFlower iPhone App Helps Refugees Fight Poverty". Retrieved 2012-01-31. 

External links[edit]