I frequently follow discussion on Hubski that I didn't take part in. To do so I either need to save the search or browse down the list to find the post I am interested in.
Saving searches to follow a discussion is frustrating. Until you go to the save you don't know if there is any new content to view. Going through the list to find the posts I want to follow is worse, but probably the option I use more often. Both methods feed my personal neurosis that I generally try to avoid engaging in, obsessive internet digging and clicking, trying not to miss something.
Being able to follow a post or even a specific thread could be a great solution to following the conversation and content that interests each of us as individuals. After you follow a post or thread new information would pop up like a reply in your inbox, or to avoid a ton of traffic you could just get a message that said "-user name- has posted to -post name-" I mentioned it to mk and he seemed interested in looking into it as a feature and I am wondering if anyone would find value in this kind of functionality?