I'm not sure what you'd like clarification on. :) I hold the same opinion today as I did then -- you can't build a community around tags. The OP is exactly right on the interpretation of what I wrote: "His point seems to be that discussion will differ depending on which tag a story is found at." (except for the dangling preposition).
Thanks for dropping by! I now realize that my reply on that thread wasn't exactly responding to that interpretation. However, your reasoning is part of why I have always been conservative about their implementation here. IMO tags work as a dimension of discovery or for editorialization (a la twitter hashtags), but that they break down when used to categorize content within a community for reasons that include the one you gave. Even so, simply having the option gives people the impression that they should be used for categorization. I think Twitter hashtags succeed in that they eat up the limited characters and have a transient nature by being embedded in the content. However, am I correct that the way you implemented them on Reddit was to alllow a post to exist in more than one subreddit at once? If so, that seems like a slightly different animal in that the communities were established, and the tags dipped the posts into these predefined spaces.
> However, I am correct that the way you implemented them on Reddit was to alllow a post to exist in more than one subreddit at once? Not exactly. Today you can post the same link in multiple reddits, since uniqueness is by reddit. You used to be able to crosspost, but we got rid of that after we expanded beyond just a few communities. With tags the implementation was that you could tag any link with any tag, so if anyone submitted the same link elsewhere and used the same tag, that link would show up in the /t/foo list once with a combined discussion thread. The alternative implementation had the link show up twice, each with their own tag. Either way, we didn't want someone to browse to /t/jesus and find links to both /r/atheism and /r/christianity.
Ah, I see. Well, then I suppose that's not too different from how they currently work here, except that you can ignore or follow specific tags. Which is funny, because one of my biggest fears with using tags is that they would turn into something akin to subreddits. :) Thanks for the explanation. It has definitely given me some things to think on. It's interesting that you don't run into a similar problem with posts on atheism and christianity popping up in /r/jesus. But then I guess the space is defended by the expectations of those that came there for jesus.Either way, we didn't want someone to browse to /t/jesus and find links to both /r/atheism and /r/christianity.