▶ JSON will be the default format for new internet APIs.
I'm not sure how to corroborate this one, but I think it's true. The most significant piece of evidence I have is that IBM even developed JSONx, a standard for representing JSON as XML.
▶ As more people use JSON, we'll see a XML renaissance, as we - for the first time - discover that XML actually gets some things right.
Didn't really happen, AFAICS. But there's this post: Why XML won’t die: XML vs. JSON for your API which says: "not everything in the world is a programming-language object". +1 to that.
▶ GHC will get typed type-level programming and end this highly embarrassing state of untypedness.
▶ We'll have a verified compiler-and-OS toolchain for compiling and running some kinds of apps. It won't be x86-based.
Unfortunately, I didn't really track this issue in 2011. There's SAFE, and maybe the O'Caml folks have something to show.
Yeah, well, that was easy. My favorite is Emscripten.
▶ Split stacks and maybe some scheduler improvements will be shown competitive with green threads in the millions-of-threads!!1! (anti-)scenario.
Nobody did this AFAIK, but I still think it's true. Maybe next year.
So, although most of the predictions were rather cautious, I'm satisified with the outcome.