Facebook is now the largest online display ad publisher in the US, accounting for 16.2% of all banner ads served in Q1, according to comScore. Analysts say Facebook made no more than USD700m last year, most of which is from advertising. This lags well behind Yahoo!, which posted revenues of USD6.5bn, mostly generated via display ads. Microsoft made around USD3bn in online ad revenue last year.
comScore estimates that Facebook served 176.3bn ad impressions in the first three months of the year, way ahead of the 132bn ads Yahoo! served on its portal and the 60.2bn ads served by Microsoft. But the data doesn't include ads that Yahoo! and Microsoft serve to other websites through their ad networks, a major source of revenue for both firms.