comScore (stylized as comSCORE.) is an Internet marketing research company providing marketing data and services to many of the Internet's largest businesses. comScore tracks all Internet data on its surveyed computers in order to study online behavior.

comScore Networks was founded in August 1999 in Reston, Virginia. The company was co-founded by Gian Fulgoni, who was for many years the CEO of market research company Information Resources, Inc. (IRI) and Magid Abraham, who was also an ex-IRI employee and had served as President of IRI in the mid-1990s.

Magid and Gian came up with the idea while working with one of the original investors in the company, Mike Santer, who thought up the concept of creating a very large consumer panel online to track online commerce. The problem was that the traditional methods in which companies were tracking online behavior would not work in tracking commerce, because of the lower incidence of buying online. Normal panels in tracking visitation would be around 20-30K and, with less than 2-3% of the population buying online, the panel size needed to be at least 1-2MM. They decided to build a very large panel using more aggressive recruiting methodology and managing for the error by using advanced statistical methods and controls. Years and tens of millions of dollars went into finding the best ways to measure online buying and other behaviors, plus the level of accuracy required for Fortune 1000 companies to buy.^{[citation needed]}