After buying Telephia, BuzzMetrics and NetRatings, Nielsen is doing a re-org its digital media measurement units: Nielsen Online and Nielsen Mobile. Of the two: Nielsen Online consists Nielsen//NetRatings and BuzzMetrics, provides measurement and analysis of Web audiences, advertising, video, blogs, cetc. Itzhak Fisher, former executive chairman of BuzzMetrics, will run Nielsen Online as executive chairman.

Nielsen Mobile joins recently acquired mobile measurement Telephia with several existing initiatives grouped under Nielsen Wireless, reports Mediaweek.  It is headed by Sid Gorham, Telephia’s CEO, who becomes president and CEO.

Nielsen RingScan, which measures downloaded ringtones, remains part of Nielsen Entertainment. More in the release here.