There's no official announcement yet of a Paranormal Activity 3 movie, but I'm pretty sure the studios are seriously considering it since the second film has already more than recouped its budget. Besides the end of Paranormal Activity 2 was left wide open for a new sequel. And Don Harris (Paramount Exec VP of Distribution) did hint at new sequel:
"The company is certainly going to take a look at making a third but will be exceedingly careful in how to go about it."
Don Harris, Paramount Exec VP of Distribution
The film is likely to explore the events following Paranormal Activity 2, with Katie who's possessed by the demon and who abducted her sister's baby Hunter. But there's also the possibility of a prequel that would shed some light on Katie's childhood.
Well, Paranormal Activity 3 hasn't been officially greenlit yet, I don't want to speculate too much about its plot. But feel free to share your thoughts below! If the scriptwriters of Paranormal Activity 3 come to this site they may well pick your ideas!
:)
Update - Director Oren Peli, who helmed the first Paranormal Activity movie and is now attached to the franchise as producer, has revealed that Paranormal Activity 3 will be released on October 21, 2011.
