[terrykohla]

It seems like what you're describing is achievable via Twitter.

Use hash-tag for a particular topic.

If you like what somebody posted (perhaps a link to their blog), you follow them and if need be you can interact with them.

[sharecred]

Theoretically, I agree with you. But since the conversation itself (comments, related posts, recognizing merit, etc.) is not the focus of Twitter - it is a good tool for emitting news, but not built as a platform/environment for meaningful dialogue or eco-system.