The Audit Bureau of Circulations has just expanded its membership with five companies that serve the mobile and e-reader content markets.

Joining the firm’s membership are Bite Sized Candy (digital magazines for iPhone and iPod Touch platforms); Pixel Mags (magazine and newspaper developer for iPhone and iPod Touch); Plastic Logic (e-reader developer); ScrollMotion (iPhone e-reader and app developer); and Sony Electronics (Sony Reader creator).

The companies represent a significant spike in that sector for ABC. Previously, only, Texterity and Zinio could be counted as part of that market—though ABC president and managing director Michael Lavery noted to FOLIO: in an email that "There are a number of other digital/interactive members involved in areas like ad serving networks, widget platforms, Web site and e-newsletter audits, and so on."

Lavery added that the new members are indicative of the action the market segment is currently seeing. "While it’s early, it’s a very active market with numerous initiatives under way now. Looking ahead, analysts predict that spending on mobile advertising will surge in the next few years. So publishers see the mobile market as an opportunity to expand their brands, reach new audiences and build a foundation for potential revenue growth."

Expanding membership in this area mirrors what publishers have been doing all along—seeking new ways to deliver their content to readers on any platform they want to receive it. Consequently, auditing and reporting services will need to adapt, said Lavery. "ABC’s board and advisory committees are actively looking at how best to augment publishers’ audit reports and statements to ensure that advertisers have access to all relevant and essential audience data, from both print and digital sources."