Almost one in three U.S. TV households – 35.9 million – owns four or more televisions, according to Nielsen.

Nielsen looks at the the most-watched TV programs during 2011

Nielsen looks at the top DVD and book titles of 2011

Nielsen looks at the most effective TV advertisements of 2011

To friend or to de-friend, that is the question. New research from NM Incite, a Nielsen McKinsey company, reveals that there are innumerable factors that help Facebook users decide to add a friend or cull someone from the fold, though knowing someone in real life is the top reason cited for friend-ing someone (82%) and offensive comments are the main reason someone gets the boot (55%).

A new report provides a snapshot of the current mobile media landscape and audiences in the U.S., and highlights the potential power of mobile commerce in the near future.

Teens have officially joined the data tsunami, more than tripling their mobile data consumption in the past year while maintaining their stronghold as leading message senders.

Streaming video on game consoles is up over last year, according to Nielsen. An October survey reveals that streaming and video-on-demand represent a larger share of usage on Microsoft Xbox 360, Sony PlayStation 3 and Nintendo Wii compared to last year.

Facebook and apps from Google like Gmail and the Android Market are the most popular smartphone apps among Android owners according to Nielsen’s latest research on smartphone usage.

An historical look at the combined television audience to the annual Macy’s Thanksgiving Day Parade on NBC and CBS.