Facebook has passed Yahoo as the second biggest referrer of online video streams for online video platform Brightcove, according to a new white paper the company created with video analytics company TubeMogul.

With 9.6% of all referrals, Facebook is second only to Google's 57% referral rate.

The data for the study came from a sample of traffic of Brightcove customers. Brightcove and TubeMogul stress that the sample does not statistically represent either the online video industry or Brighcove's entire customer base.

Facebook, however, tops Google in engagement for such entertainment as magazines and broadcasters. "This can be explained that entertainment is a more commonly shared and more engaging content type among friends connecting on the social network," the paper explains. Google, on the other hand, has higher engagement for newspapers (1:57 compared to a category average of 1:27).

But Google and Facebook were beat by Twitter in most categories. Twitter referrals had the highest engagement in brands (1:47), broadcasters (1:57) and online media properties (1:40).

Other findings for the third quarter:
-- Gaming consoles lead in average viewing time at 2:45 per view. Online was second at 2:27 and mobile was third at just over 2:00.
-- Marketers will appreciate the fact that completion rates for brand marketers (47%), broadcasters (44%) and online media properties (46%) increased in the third quarter.
-- Wednesday was the top day for total views. Brand marketers and online media had their peak views on Thursday. But people are more engaged at the end of the week; Friday was the top day in terms of average minutes viewed per video.