Not even sure whether to reply to someone’s comments by leaving another comment or by linking through to them like this.For me the answer lies in the content of the comment. If it raises an issue that I want to discuss further or feel I should address further, a new post on the blog linking to the post with the comment seems to me to be the most appropriate. If I want to really respond to the comment, this seems better because there is a better chance that it will be read. But that assumption could be entirely inaccurate.
If someone makes a comment that is nice but not necessarily extending the discussion, I may just comment after the original comments to say thank you. That is what Clarence Fisher does here. It is very appropriate, I think. But it would probably have been just as appropriate to write another post about the support he received -- if he had wanted to.
Another option, and the one that the Literacy Adviser used, was to leave a comment on one of my blogs acknowledging that I had commented on his blog. To me this is OK, too, but it is a little awkward as the comment and the post aren't necessarily connected. But I know I have received a number of comments like that, so a lot of people must do it.
I don't know that there is a real protocol for this. Or if there is, someone forgot to tell me. So now is your chance: What should bloggers do when they want to comment on a comment? Bill and I are both anxious to know.