Nielsen is probably still best-known for its famed TV ratings system, but the huge research firm isn't ignoring the digital space — it just released its Q4 2011 "cross-platform" report, which looks at how many people view video across multiple screens, and for how long. While there weren't any major trend shifts at the end of last year, Nielsen did find that both the number of people watching "traditional" TV (broadcast or cable) declined for the third consecutive quarter, as did the amount of time spend watching. 284.4 million people watched traditional TV in Q4, down from 289.3 in Q4 2010; the average amount of time spent watching TV per month declined slightly to 153 hours and 19 minutes per month, down from 154:05 a year ago.

Still, traditional TV watching dominates the other categories Nielsen ranked, including the viewing of timeshifted TV, videos online, and videos on a mobile phone — but all three of those categories have been steadily growing over the last 8 quarters. Nielsen's data shows that 147.4 million people watched online video in Q4 2011, up from 141.4 million in Q4 2010; that beat out out the 113.5 million who timeshifted TV, which was up from 105.9 million in the quarter a year earlier. Mobile phone video viewers trail all the rest, with 33.5 million viewers, up from 24.7 million a year earlier. All three categories have experienced slow but steady growth, with Q4 2011 representing the seventh consecutive quarter of growth in all cases.

While time spent watching traditional TV declined slightly, consumers spent a good deal more time watching timeshifted TV in Q4 — the average of 11 hours and 44 minutes per month was up 10 hours and 27 minutes in Q4 2010. It's a nice bump, but it still trails traditional TV by a wide margin. Internet viewing and mobile phone viewing didn't get a similar increase — both were flat year-over-year, with internet video viewers spending four hours and 34 minutes per month, compared to mobile phone viewers watching for four hours and 20 minutes per month. There are a lot of different ways to look at Nielsen's data, but one thing is abundantly clear — its research shows that most people still watch traditional TV, and spend a lot more time watching there than on other products. Perhaps the cord-cutting revolution is still a ways off.