Return of the LINK method
In 1997, RFC 2068--think HTTP/1.1 "beta"--defined a LINK method so that editors could send link requests to each other. Here's an example request which states that relify.com is "about" RFC 2068:
Link: <http://relify.com/>; rel="about"
And in response:
HTTP/1.1 202 Accepted
202 is used to minimize the risk of Denial-of-Service attempts.
Later, between 1997 (the publication date of RFC 2068) and 1998 (the launch of RFC 2616--HTTP/1.1), no one had attempted implementation (at least not at a sufficient level for the editors--and the LINK method was removed from the HTTP/1.1 spec (along with UNLINK, PATCH, and Link headers).
Relify project aims to bring it back with the help of draft-snell-link-method-12 as a guide--which couldn't have showed up at a better time! Here's some early thoughts on bringing LINK & UNLINK back by James Snell.