Your typical end user doesn't switch IPs that often, so it's fine to Anubis them again when they do. A scraper, on the other hand, has a tradeoff to make between rotating ips often (requiring a challenge on every request) or keeping only a few IPs (making cross-request identification much more valuable and reliable).
> That’s why Anubis does an up front challenge and then you’re good for a while. It’s a really low cost for the scrapers.
Except that doing hundreds of requests from the same IP makes it pretty trivial to detect scraping, opening you up to being banned, or fun stuff like a slowloris or being fed poisoned data.
There are major websites that take more than 2-3 seconds to load every new page. Google, for example. Reddit. Facebook. Instagram. Doesn't seem to have hurt them.
Your typical end user doesn't switch IPs that often, so it's fine to Anubis them again when they do. A scraper, on the other hand, has a tradeoff to make between rotating ips often (requiring a challenge on every request) or keeping only a few IPs (making cross-request identification much more valuable and reliable).