Dive Brief: 

• Facebook's long awaited auto-play video ads are set to debut this week and may be a strong competitor for Twitter's Promoted Trend product. 
• Twitter's Promoted Trend has been popular among TV brands, but to see a video, users have to click through a static ad. Facebook's video ads begin automatically. 
• Twitter struggles a bit already to sell the Promoted Trend spot every day and had several days in November with no buyers. 

Dive Insight: 

While it seems like auto-play videos may alienate Facebook users, Gartner social media analyst Brian Blau makes a good point "that commercials on your cable box are auto-play." Users may not be used to auto-play on Facebook, but the TV industry is already warmed up to the idea. This may be the advantage that hurts Twitter's ad business a bit. Twitter still has the advantage of a much more affordable product, however, with a $200,000-a-day price tag compared to Facebook, which can cost as much as $2 million a day.