Does anybody remember a quote by Tim Berners Lee where he says that links on the web are "one-way" because it's very easy to store an outbound relation with the content, but tracking inbound links increases the complexity of the system significantly.
Ted Nelson was into two-way links and tbl just said screw it we're doing one-way on the web and knocked off 95% of the complexity.
I seem to recall reading that, but I can't find it.
PS: this thought brought to you by #webmentions
I found this about ted nelson's ideas: http://www.ted-hunt.com/HYPERLINKS/index.html