I actually had added this to our list of things to look into when there is time, but forgot to update the thread with that fact—sorry about that! Thanks for digging up these links.
Great to hear that this is being looked into (when you have the time to do so)! I would love Scrivener to support Skim annotations and the Skim PDF-engine for creating annotations and other markup elements. As pointed out by OP, it would make Scrivener even more attractive as an integrated research and academic writing tool!
EDIT: I am also guessing that the problem of white boxes on PDFs in Scrivener due to a bug in Apple’s PDF Engine (viewtopic.php?f=2&t=27470&start=0&hilit=white+boxes) would also be fixed by utilising Skim’s PDF-engine, as I have never experienced this issue while using Skim.
Skim uses the same PDF engine and Scrivener, so that would make no difference - Skim just adds some extra features to the standard engine, as I understand it. The white boxes problem is down to Scrivener being 32-bit, whereas Skim is 64-bit. I have a 64-bit version of Scrivener in the works that should fix that. I’ll look at the Skim API eventually, but because of how much else I have to do, I doubt it will be before this time next year, I’m sorry to say.
I’ve been using Skim since 2005 but I can’t imagine it being a priority for anyone until there’s an iOS solution for viewing Skim annotations. It predates native PDF annotation on the Mac, and has a lot more capabilities, but the constant need to import/export annotations going to/from iOS is burdensome.
