alt Hacker News> Scrapers can't change their strategy?
Yes, but you normally don't try to fight all strategies up front, you add stuff on a need-to basis. Currently, lots of people are in the stage of "need to get this thing using bunch of IPs to stop hammering my servers", apparently Anubis helps them with that. If that stops working, other tactics are tried, and so it goes on for the life of your service. Hasn't stopped yet, doesn't seem to be stopped soon either.
That argument also works against anubis. Why bother forcing clients to solve a PoW challenge, when you're fighting a bunch of unsophisticated attackers that will be deterred by a javascript challenge that requires them to solve `result = x + y`?