I know it would be instantly spammed to death, but I wish blogs and comment-allowing sites like hackernews would allow me to post my response on my own blog, and then republish it on their blog. There have been attempts at this but no one has gotten it right so that the responses flow together properly.
Tumblr as an integrated system with their reblogging offers something like this, and twitter conversations are like this if you use a tool to examine the conversation - but it only works well if the conversation doesn’t leave their system.
