When working on your building your blog, it’s always important to remember that blogging isn’t a one-way street, and that you aren’t the only writer involved.
Blogging is as much about the content you create as it is about the people reading (and responding to it). The Discussion Settings screen gives you control over who can comment, as well as when comments will be held for moderation, and other options.
Hope this helps with the discussions on your blog. If you have any questions, leave them in the comments!