According to comScore’s latest monthly report on online video usage, Google – driven primarily by the performance of YouTube – drew 157.2 million unique viewers to its video offerings in December. That marked a 9 percent rise from December 2010 and represented 86 percent of the total internet audience for the month, according to comScore.

And with YouTube focusing on longer form, professionally produced video in its dedicated “TV” channels—not to mention other offerings like full-length movies—usage per unique viewer shot up 72 percent year-to-year to an average of 471.9 minutes per viewer.

The top 10 dedicated video channels all have homes on YouTube, with music channel VEVO ranking first, Warner Music second and game channel Machinima third. Yahoo (NSDQ: YHOO), which has also been aggressively building content channels, had a 6 percent year-to-year rise in unique video viewers to 53.3 million, while Hulu saw its unique viewers spike 18 percent to 31.2 million for December, according to comScore (NSDQ: SCOR).

Facebook saw only minimal growth, 2 percent to 42,024 unique viewers, over Dec. 2010.

Some other highlights from the comScore report:

—Hulu once again delivered the most video ad impressions with nearly 1.5 million ads rendered in December, up 22 percent from the same month in 2010.

—Across the entire internet, video ad deliveries increased 20 percent to 7.1 million.

—181.7 million U.S. Internet users watched online video content in December – up 6 percent over 2010—for an average of 23.2 hours per viewer (up 59 percent). The U.S. Internet audience watched nearly 43.5 billion videos last month.