Companies can now find out where internet marketing display ads are being viewed online with the help of a new tool from comScore.
The new Ad Metrix measurement service provides competitive intelligence for online display ad campaigns including static banners, rich media and video ads.
It shows which sites are ranked as the top display ad publishers each month and also reveals which companies are the top web advertisers.
The tool also provides insight into the demographic composition of the audiences being reached by the ads.
This will allow internet marketing teams to make informed decisions about where to launch their next campaigns.
Mike Read, managing director of comScore Europe, said: "Never before have the tools associated with traditional media measurement been so closely aligned with online accountability metrics."
According to comScore, Facebook ranked as the top UK display ad publisher in April with 12.5 billion ad views.
Google predicted recently that Facebook could come to rival traditional search engines as web users increasingly rely on their friends and peers for recommendations and advice as opposed to search engine results.