The Paranormal Activity franchise has been successful primarily due to the fact that they utilize trailers and make them seem interesting and/or good. I have never been a fan of these movies but I did admit that I thought the trailer for Paranormal Activity 3 made it look decent. However, that movie was just as much of a shit show as the previous ones were.
With that said, the trailer for Paranormal Activity 4 makes the movie look decent. I am not putting any interest in this one due to the fact that I have figured out the tricks by now. Not to mention that most of the footage they use in the trailers isn't even in the movie. That is another thing we learned from the 3rd movie. If I get bored enough I'll go see it, I guess, but I am not counting on it.