[LeBeakofJustice]

Kawahara claims the story is non-canonical, but he recycled so many ideas in Accel World that it's hard not to imagine AW as being SAO's future.

I think one example of this is the nerve gear.

In one of the Accel World episodes,

Spoiler for Context:

While Haru was researching old technology in order to find out how Noumi's name stayed hidden

Haru saw a picture of a helmet like the one Kazuto uses on a website that looks like Wikipedia.