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