I am very curious on this subject. Would it be illegal to stream anime on a website without the owners permission? If so how do many websites on the internet do it without getting in trouble?
Would it be illegal to stream anime on a website without the owners permission?
Yes, as Hakase explains you need an licenses to do so. sometimes yes you need a trusted/popular site however if your new to the game and don't have a website you should already be a trusted/popular entity (such as a company). either way you should be getting the money to afford the license you need.
If so how do many websites on the internet do it without getting in trouble?
a couple of reasons are stated here in Logan M's answer but they pertain to fansubs. but as for non-fansubs (like some sites which will host licensed English episodes of a series) it's only a matter of time.
Torrent Sites which allows the downloading of other content including TV series (anime aswell) get taken down alot these days and recently Australian ISPs began to block such sites (if not being half-assed about it) while some copyright holders have tried to make ISPs hand over the Customer Details of those who pirate1.
the only i see that stops these sites getting DMCAed is that in the west anime is still kinda niche and thus don't get the huge announcements like "New Game of Thrones season starts ##/##/####" or "[INSERT NAME] revealed to replace Peter Capaldi as the 13th Doctor". hell the later when Peter Capaldi was announced there was a red carpet event for it. if anime became more mainstream these sites would get more of the spotlight and quickly get taken down.
while i have my reservations of streaming sites there are already quite a few which do it legally and these have the benefits of not running non-QAed ads which could lead to malware being installed, being more stable with their hosted files and general better performance in terms of load times. so really there is no need to be using an illegal site unless you don't actually like anime and don't want to support the parties that bought it to you.
browser private/incognito modes only stop cookies/session/history from being saved on your PC. these sites and ISPs can still record your IP
It would only be legal to stream any anime when you have acquired the licenses to do so. You'd have to make an agreement with the intellectual property holder (production company or the distributor), and they won't sign with just anyone − they want trusted sites which would be visited by enough users. And these licenses have limited time frames. It also costs a lot of money. The exact number varies case by case, but it's safe to say it would cost a fortune to an individual.