Disney-ABC has been an online video leader since back in 2005 when it struck the first network deal with iTunes. Since then, ABC has continued to innovate with its video player, and has also won awards for the user experience, so I always pay extra attention to its online video initiatives. Just this week, ABC Family launched a weekly Web series for its hit show “Pretty Little Liars,” and the first episode logged more than 250,000 views in less than 24 hours, the network said. The premise of the Web series and its social strategy is a good fit for the show. Given the show’s social reach, the network will promote the Web program aggressively on social channels by posting “mysterious” clips and photos from the series on Facebook, Twitter, Tumblr, and Pinterest. Social TV service Bluefin said the on-air finale on Tuesday hit a social TV record with 1.6 million social media comments for the episode. The Web series is called “Pretty Dirty Secrets” and it’s designed to bridge the time between the show’s summer finale and a special Halloween episode running in late October, with regular episodes to return in January. Each Tuesday for eight weeks, the network will run a new Web episode online at ABCFamily.com at 8 p.m. EST and the digital shorts will focus on the local Halloween store in Rosewood as it preps for the holiday. ABC Family tells me the goal of the Web show is to provide something special to keep its millennial fans hooked during the hiatus, and to give them something to talk about every Tuesday that is connected to the upcoming holiday special. That’s a smart strategy to keep the social fires burning. According to social TV tracking service Trendrr.TV, "Pretty Little Liars" had the largest engaged audience based on total activity and average activity per telecast in the month of June for a cable show. The Web series also serves as a vehicle to introduce the character of “Shana” who will later appear on the series in 2013. The first Web episode is a promo clip, but ABC Family showed me a sneak preview of the upcoming arc and I’m impressed. The Web series stars some series regulars and it also has that "Pretty Little Liars" vibe and just enough content in a two-minute episode to feel like a story is unfolding.