> The benefit of having only one implementation of a protocol is that the protocol can evolve much faster. Or you design the protocol to allow non-standard ext

> The benefit of having only one implementation of a protocol is that the protocol can evolve much faster. Or you design the protocol to allow non-standard extensions, like with SSH, so you can have foo@example.com implemented by one product (and others can look for it if useful), and bar@example.org by another product. And if enough folks file the feature(s) useful they can be standardize with tweaks that fixed issues that were found though operational experience. Lots of IETF standards have a "x-" prefix mentioned for private / proprietary extensions.