ddos means distributed denial of service- you don't need a ton, just one person that is very industrious. Odds are the ddos attack was aimed at another website hosted by avalon's ISP so it started affecting avalon as well as the broadband usage got maxed out.
Also, Japan would have no reason, to my knowledge, to ddos another site unless it was some sort of rare combined effort from 2ch (doubtless). It was probably people from europe/the us using japanese, russian, and chinese proxies, amongst others.
And, oddly enough, since I'm currently living in Tokyo, I was one of the people cut off periodically over a course of three days due to the ISP probably thinking I was one of the hackers. *chuckle*
Oh, and I didn't mean doubtless, I meant doubtful- sorry, I've had one too many suntory chu-hi's. It's sakura season, afterall!
Written by my hand on the 13th of Leaflost, in the year 1231.