Facebook has passed Yahoo in video viewership, according to August data released by comScore. Facebook climbed to number two with over 58.6 million unique viewers and a total of 243 million viewing sessions, while Yahoo settled for third place with 53.9 million viewers. Google's sites still lead the pack with more than those in second and third combined: 146.3 million viewers and 1.9 billion viewing sessions.

In August, a whopping 178 million people watched online video content in the US (unchanged from July) at an average 14.3 hours per viewer. 85.1 percent of Internet users in the US viewed online video last month, adding up to more than 5.2 billion viewing sessions in total.

Americans viewed more than 3.8 billion video ads in August, up from 3.6 million in July. Hulu generated the highest number of video ad impressions at 790 million, with an average of 30 ads over the course of the month. The duration of the average online video was 4.8 minutes, while the average online video ad was 0.4 minutes. Video ads accounted for 10.7 percent of all videos viewed and 1.0 percent of all minutes spent viewing video online.