AT&T was closely followed by Verizon with 5.7 billion views (1.8%), while Vonage ranked third, with 4.3 billion (1.3%). Not far behind was Sprint, in sixth place, with 3.2 billion views, or 1% market share.
Yahoo ranked as the top display ad publisher in March, with a 13% share, followed by Fox Interactive (9.7%), Facebook (7.7%), Microsoft sites (5.5%), and AOL (5.4%). Comparing those figures to ones released at the start of last year suggests Facebook is taking display ad share from the major Web portals.
When comScore released similar data in Feb. 2008, Facebook had only a 1.5% share compared to 19% for Yahoo, 16.5% for Fox, and 6.7% for Microsoft.