Very popular with Opera users and users who are very eager to read events that do not exist from randomly inactive pubkeys.

I don't know, I've spent countless hours trying to improve or fix this situation. I can't identify any blockable pattern aside from the tons of traffic already being blocked, but I also don't have experience with this stuff. It does feel very erratic and nonsense, and coming from a large number of IP addresses, but it's probably not a targeted DDoS in the classic sense.