> Lots of sites have ToS preventing such things, are those legally void now? Are captchas on public pages illegal, even if you request the page 8000 times in a second?
ToS are subservient to the law; you can (probably) terminate a service account from a user that breaks your ToS, but if the user does not have a service account (as is the case for HiQ, it doesn't seem they were using accounts for it), then your ToS does not apply, since you've technically not entered a binding legal contract with them.
> This is almost weirder. If LinkedIn wanted to force users to sign in to view profile info, would they be not allowed to do that because some company had signed a contract that implicitly assumed access to that data? If someone writes a web scraper for my site, and I unknowingly change my site in a way that breaks that scraper, can a court force me to revert the change?
IANAL, but I believe that'd fall on intent, and intent is often difficult to prove at a personal level, but not necessarily at a company level. If your intent for putting up barriers that happen to impact scraping, whatever they may be, was indeed to knowingly prevent scraping from a particular company, then you may be liable under this decision. This is the only part of the decision I'm torn on, since it's a bit messy to really prove such things. I'd be much more comfortable with allowing companies to take whatever measures they feel necessary to prevent scraping, and also allowing scrapers to legally circumvent those measures without threat of prosecution, assuming they didn't actually hack into anything.