Most savvy internet users should be familiar with at least a few HTTP status codes. 404, for example, is a common code that informs users when a page can't be found, and you've probably come across others before, such as 403 (forbidden), 500 (internal server error), and 301 (moved permanently).
The Internet Engineering Task Force (IETF) has now come up with a new status code that will inform users when a page has been taken down or removed for legal reasons. The code, 451, will be accompanied by an error message stating that the web page is "unavailable for legal reasons."
Any pages that display status code 451 should also include an explanation of why the page was removed for legal reasons, including who made the claim, what legislation allows them to make the claim, and who it applies to. The code can also be used by ISPs and DNS providers to identify who blocked the page, if the page wasn't blocked by the website host itself.
An example of the code in use is as follows:
HTTP/1.1 451 Unavailable For Legal Reasons
Link: rel="blocked-by"
Content-Type: text/html
Unavailable For Legal Reasons
This request may not be serviced in the Roman Province of Judea due to the Lex Julia Majestatis, which disallows access to resources hosted on servers deemed to be operated by the People's Front of Judea.
Status code 451 is ready for use right now, after the IETF voted to officially include and support the status code in a unanimous decision. There are still some minor adjustments to be made, and polish to be added, but you should start to see 451 error codes pop up throughout the internet in the near future.