Org-mode has all of this. Non-proprietary? Easy capture? Indexing? Search? Agenda? Mobile-capture and sync? Org-drill for spaced repetition? Integration with snippet capture in browser?

Every single one checked.

I used MobileOrg for a while but couldn't figure out a seamless workflow to eliminate manually pushing and pulling on the desktop. Automatic HTML export to dropbox works fine for mobile viewing, though.

How do you do the indexing part?

Is it possible to record audio with org-mode (and then categorize/annotate)? And do quick drawings with a stylus on the screen?

> Is it possible to record audio with org-mode (and then categorize/annotate)?

I haven't seen any plugin to do audio recording from Emacs, but it should be easy (if you're willing to dig into elisp a bit; it's not hard) to invoke any kind of CLI tool for that, and then a/ move the output recording to a proper place, and b/ capture the link for org-mode.

> And do quick drawings with a stylus on the screen?

There are picture-mode and artist-mode in Emacs for that, but I haven't tested any of them with a stylus and a touchscreen, and draw in text mode.

Images and video?

Sure, Emacs can display images inline if you want it to, or just open it in another buffer ("tab") or with an external application. You just store the image in a separate file and make a link in your org-mode text file.

As for videos, I don't recall Emacs being able to play them directly, but you can easily invoke an external player.

images are important, that's how I learn countries (point on map) and birds

Agree on the brains comment for lowest latency cache, http://artofmemory.com/ - are you using Anki for language learning? Desktop or mobile? Does each user create their own cards or are these available as pre-existing content (free or paid)?

I don't learn a new lang atm but I've heard it works great for that.

There are shared decks [1] and you can create your own very easily. Whenever I stumble over a new fact throughout the day, I (try to) add it to my deck. To test the system, I learned all european countries with capitals and all US states in 4 hours total (spread over weeks, just 1-2 minutes spent every other day). It's really easy and fun.

I use both the desktop and the mobile apps, they keep in sync.

[1] https://ankiweb.net/shared/decks/

Unbelievable list of decks & add-ons. Why doesn't someone give Anki $$$$$? This is how humans will compete & interoperate with robots/algos. The format should be at least as important as ePub.

I don't see any licensing or copyright terms in the list of shared decks, are those usually specified within each deck? A web search turned up this discussion, http://lesswrong.com/lw/k7a/proposal_community_curated_anki_...

The deck sharing web app could need some serious polish (if not rewrite as a modern web app). Something like fork/pull requests and diff would be awesome. That would encourage people to contribute back and fix bugs in the decks.

I don't know about licensing/copyright of the decks.