[mindcrime]

FWIW, the reason I'm familiar with the "stack" mentioned above is exactly because we're working on something like that. Our focus is more in internal knowledge than the general web, but there's no reason that overall methodology couldn't be applied more widely (although making it all scale is a technical challenge to be sure!). I could see us offering a "knowledge graph API" service of some sort down the road, depending on how other initiatives shake out.