The desire to focus #edchat on several voted on topics a week makes me think about the value of Twitter as a platform for focused conversation, even with the hashtag. It seems to me as if anybody could use this hashtag at any point. I'm not even talking about spammer. But, for example, if I have an intriguing education question I might want the people at #edchat to respond. Now that I understand the goals of #edchat I wouldn't do this, but if I hadn't understood the goals I might have posted my comment with this hashtag.
I particularly like the use of nings for focused conversation. If you like what I have to say you can respond to it, otherwise you don't have to. But, within this larger network, there is a place for me to post my own topic.
Does this make any sense?