I'm inclined to believe this. There was mention of the NicoNico thing on the "other" forum, but that's as far as it went with international announcements.

60k is a huge number, considering you had to have a premium membership on NicoNico to even view the live stream (there were places that were re-streaming it lol). So yeah, I do think SAO's timing had a lot to do with the interest in online gaming in Japan, even if it's just a passing fad.