ComScore brings to the party a panel of 350,000 web users who also participate in loyalty card programmes, allowing the research agency to identify which visitors to a site are most likely to purchase a particular brand or product in a retail store.

Microsoft advertisers, including Campbell Soup Company and Alberto Culver, can then use this data to define and find their target audience across the Microsoft Media Network.

ComScore gives the example of a cereal company that wants to reach women aged 30-54 who used to purchase a particular cereal brand but haven’t recently made a purchase.

“Microsoft can find an audience based on the ComScore Audience Advantage model that fits the cereal company’s key consumer criteria,” said the company. “Microsoft can then create lookalike customer segments and serve ads to people with similar characteristics across Microsoft’s online properties.”

Post-campaign, ComScore says, it can compare the sales trends for panellists who saw the ad against those who didn’t – thus providing an estimate of the incremental sales effect generated by the online advertising.