Quantcast is an American technology company, founded in 2006, that specializes in audience measurement and real-time advertising. The company offers public access to traffic and demographic data for millions of web sites and detailed user insights to digital publishers enrolled in its Quantified Publisher Program. Their data centers process more than 800,000 transactions per second and the company states that it produces accurate audience measurement to over 100 million web destinations. As of 2013, it was said to be one of the world's top five big data processing organisations. Its headquarters is in San Francisco, with offices in New York, Chicago, London and Dublin.