We're big fans of "Paranormal Activity 3" -- we think it's easily the best of the three films so far -- but the movies are best enjoyed on a visceral level, rather than on some sort of ongoing storyline. Frankly, coming into the third film, we had completely forgotten everything that had happened in the first two films, who the characters were, whether this was a demon or a ghost haunting them, all of it. We vaguely remembered Katie Featherstone, but only because she's the only person who has been in all three movies. What more is there to know?
A lot, apparently! Brad Brevet, the intrepid sort behind the Rope of Silicon blog, appears to be the only person we know who cares about the "Paranormal Activity" mythology and has put together a helpful guide to how the three stories tie together (apparently they do!) and what we should expect from the fourth installment, which we'll all be typing about on this site in precisely 357 days. He gets pretty far into it, and we learned all kinds of things we didn't know. Here's a fun (spoiler heavy) example, trying to explain why Micah from "Paranormal Activity" refers to a mother, a mother who appears to die at the end of "Paranormal Activity 3," and why neither sister seems to remember anything that happened in the third film when they're grownups:
The way I explain these two potential plot holes is to say that 1) The mother Katie and Micah are referring to is an adoptive mother set up by the grandmother, or potentially a step-mother if the grandmother then handed the two children off to their biological father; and 2) Katie and Kristi have a hard time remembering what happened because they have been brainwashed as is referenced in the third film and the effects of that may have muddled their memories. Either that, or what they are largely remembering is what happened when they were a little older, most likely what will be found on the 1992 tape seen at the beginning of Paranormal Activity 3.
Makes sense! Though we hope Brad doesn't try to keep all this together through the inevitable fourth, fifth and sixth films, because it's sort of obvious that he's thought about this a lot more than the filmmakers (or the audience) has.