allowed the company to statistically estimate the number of Americans watching TV and the demographic breakdown of viewers. This became an important tool for advertisers and networks. In the 1980s, the company launched a new measurement device known as the "people meter". The device resembles a remote control with buttons for each individual family member and extras for guests. Viewers push a button to signify when they are in the room and push it again when they leave, even if the TV is still on. This form of measurement was intended to provide a more accurate picture of who was watching and when. In July 2008, Nielsen released the first in a series of quarterly reports, detailing video and TV usage across the ‘three screens’ – Television, Internet and Mobile devices. The A2/M2 Three Screen Report also includes trends in timeshifted viewing behavior and its relationship to online video viewing, a demographic breakdown of mobile video viewers and DVR penetration. On September 30, 2016, Nielsen made its Digital Content Ratings available in full syndication for clients. On September 9, 2016, Nielsen announced that it would retire its paper TV diaries by mid-2017 and provide all electronic measurement in its local television ratings. Private equity Nielsen was acquired by the Dun & Bradstreet Company in 1984. In 1996, D&B divided the company into two separate companies: Nielsen Media Research, which was responsible for TV ratings, and AC Nielsen, which was responsible for consumer shopping trends and box-office data. In 1999, Nielsen Media Research was acquired by the Dutch publishing company VNU (Verenigde Nederlandse Uitgeverijen). VNU later acquired AC Nielsen and recombined the two businesses in 2001. In between, VNU sold off its newspaper properties to Wegener and its consumer magazines to Sanoma. The company's publishing arm also owned several publications including The Hollywood Reporter and Billboard magazine. VNU combined the Nielsen properties with other research and data collection units including BASES, Claritas, HCI and Spectra. VNU also acquired companies that added to its measurement capabilities. Becoming a public company Nielsen was a private company from 2006 through 2011. On January 25, 2011, the company listed itself on the New York Stock Exchange and issued an initial public offering (IPO) that raised $1.8 billion in the largest private equity-backed U.S. IPO since 2006. Mergers, acquisitions, strategic alliances and divestitures 2004 Nielsen began a joint venture called AGB Nielsen Media Research with WPP