ComScore Video Metrix reported that 178 million Americans watched 33 billion online content videos in February, while the number of video ad views reached 9.9 billion. Is this up, down or sidewise from previous reports?

Because comScore introduced three important methodological changes to its estimates with the release of the August 2012 U.S. Video Metrix data, it’s not possible to do a year-over-year comparison of data.

But, in August 2012, all-time high of 188 million U.S. Internet users watched 37.7 billion online content videos, while video ad views totaled 9.5 billion. So, it appears that 5.6 percent fewer Americans are now watching 14.2 percent fewer online content videos, but 4.2 percent more video ads than they were seven months ago.

Does this make sense?

For starters, there are 31 days in August and only 28 days in February. And Americans may watch more video during the summer than they do during the winter.

Nevertheless, 83.3 percent of the U.S. Internet audience viewed online video in February 2013, compared to 87.3 percent of the U.S. Internet audience who viewed online video in August 2012. And the duration of the average online content video was 5.6 minutes and the average online video ad was 0.4 minutes in February 2013, while the duration of the average online content video was 6.7 minutes and the average online video ad was 0.4 minutes.

So, marketers will want to watch closely to see what happens when comparable data becomes available for August 2013. Then, and only then, will we know if online video viewing has hit a wall, or if we’ve merely entered a new era where the market moves sideways.

Either way, it’s clear that a rising tide is no longer lifting all the old boats. There are winners and losers in the latest data.

In February 2013, Google sites, driven primarily by video viewing at YouTube, ranked as the top online video content property with 150.7 million unique viewers, followed by Facebook with 61.2 million, VEVO with 49.5 million, NDN with 46.3 million, Yahoo sites with 43.6 million, Viacom Digital with 39.1 million, Microsoft sites with 36.7 million, and AOL with 35.3 million.

More than 33 billion video content views occurred during the month, with Google sites generating the highest number at 11.3 billion and Facebook reaching its all-time high of 558 million.

Back in August 2012, Google/YouTube ranked as the top online video content property with 150.2 million unique viewers, followed by Yahoo sites with 55 million, Microsoft sites with 53.7 million, VEVO with 49.3 million, Facebook with 47.7 million, AOL with 45.7 million, Viacom Digital with 38.7 million, and NDN 37.5 million. Nearly 37.7 billion video content views occurred during the month, with Google sites generating the highest number at 13.8 billion, followed by AOL, Inc. with 725 million.

In other words, Facebook is up 13.5 million, NDN is up 8.8 million, Google sites are up 0.5 million, Viacom Digital is up 0.4 million, and VEVO is up 0.2 million – despite the shorter month and different season – while Microsoft sites are down 17.0 million, Yahoo sites are down 11.4 million, and AOL is down 10.4 million. So, the obvious winners are Facebook and NDN, and the clear losers are Microsoft, Yahoo, and AOL.

In February 2013, Americans viewed 9.9 billion video ads, with Google sites ranking first with its all-time high of 2.2 billion ads. BrightRoll Video Network came in second with 1.6 billion, followed by Hulu with 1.4 billion, and Adap.tv with 1.4 billion. Time spent watching video ads totaled 3.8 billion minutes, with BrightRoll Video Network delivering the highest duration of video ads at 859 million minutes.

In August 2012, Americans viewed 9.5 billion video ads, with each of the top 4 video ad properties delivering more than 1-billion video ads. Google sites ranked first with more than 1.7 billion ads, followed by BrightRoll Video Network with 1.4 billion, Adap.tv with 1.2 billion, and Hulu with 1.1 billion. Time spent watching video ads totaled 3.5 billion minutes, with BrightRoll Video Network delivering the highest duration of video ads at 717 million minutes.

So, Google Sites is up by 0.5 billion ads, Hulu is up 0.3 billion, BrightRoll Video Network is up 0.2 billion, and Adap.tv is up 0.2 billion. But comScore defines “video ads” as streaming-video advertising only and do not include other types of video monetization, such as overlays, branded players, or matching banner ads.

So, the overall market for online video is up for some content properties and down for others. It’s also moving sideways. It is worth noting that comScore’s doesn’t include Twitter’s Vine app, which lets marketers create and share short looping videos that are six seconds long.

Here’s what Mashable was able to do with Vine to celebrate Pi Day.

So, don’t get lulled into thinking that the online video market has plateaued. It may just be moving sideways.