Paramount is enlisting fans to decide which 25 cities around the world will get exclusive advance screenings of “Paranormal Activity 4.”The franchise has a history of using social media to market its films: In 2009, it enlisted the website Eventful and asked fans to click “Demand It!” to get special premieres of “Paranormal Activity” in their towns, a campaign it repeated for the sequel. For the third film, Paramount used “Tweet To See It First!” to choose 20 cities in which to advance-screen the pic. It’s a similar story for the fourth installment: Fans can now vote to bring the free advance screening to their town by clicking “Want It” on the film’s Facebook page or website. The application uses geotagging based off fans’ Facebook profiles to track which cities have the most votes. A display also shows the info in real time — as of Wednesday, Lake Bluff, Ill., Purchase, N.Y. and Fresno, Calif. were the top three cities in the voting, with Los Angeles at No. 24. “The success of ‘Paranormal Activity’ began with the fans who have championed the movie franchise from the very beginning through social media,” said Amy Powell, exec VP of interactive marketing at Paramount. “Paranormal Activity 4,” helmed by Henry Joost and Ariel Schulman, opens Oct. 19.