Facebook is once again looking to boost revenue by adding additional ad spots to their already crowded lineup of ad options. This new spot will only apply to live broadcasters, and even then only those who are getting 300 or more concurrent viewers.
At this point this is still in testing and applies to only non-live videos (replays). After four minutes of the video, the ad will break in for 20 seconds, before it continues to complete the replay. The testing is being conducted with just a few publishers at this point, but assuming everything goes according to plan, it will likely roll out to a broader audience later this year.
This type of ad spot really makes a lot of sense given that other video publishers (YouTube) are already running mid-video ads with a lot of success. In addition, people are used to this type of interruption because that is how television ads have always been.
For now at least, Facebook is limiting how much control advertisers will have on what videos their ads are playing on. It is likely that this will change if this type of ad spot gets a wider roll out. For now, however, only larger scale videos are eligible for this type of ad anyway so it is unlikely that there will be too much in terms of conflict or questionable content.