An article by MediaPost reports on a recent report by comScore in June which identified social networking as the fastest-growing content category across both mobile browsers and applications. This expansion comes as no great surprise, given that there are estimated to be 100 million people worldwide accessing Facebook on mobile devices.

Further data from mobile ad network Millennial Media claims that there has been a 50% rise in mobile ad campaigns that send users to multiple social networking sites in the last six months. Overall, 12% of campaigns direct people to social sites as a call to action within ads, which is a higher proportion than those sending users to mobile commerce sites or store locator maps.

The report says that whilst mobile advertisers are increasingly trying to drive users to brand pages or promotions on social sites, click-to-call remains the most common type of action they encourage in ads at 36%, followed by signing up for a service (29%), submitting a form (28%), application download (24%) and watching a video (23%).

Other data covered by the Millennial report show that the number of ad requests per page view was just over one (1.03) and the average monthly page views per user was 108. The average session time was up by a minute to five minutes.