When responding to a blog audience, be succinct and keep the conversation moving. Blog conversation is a two-way street, and exchanging ideas makes compelling content. At the end of each of your responses, conclude with a question, such as "What's your take on that?" or "How do you feel about this?"
Be prepared for the occasional rude or embarrassing question. For example, if your book is about barbecuing, be ready for questions from animal-rights activists. Feel free to ignore off-topic comments, and simply continue with your message. But don't shy away from substantive arguments--nothing sells a book better than controversy.
At each stop on your blog tour, mention your previous appearances on other blogs and provide the links. This will generate continued readership and cross-linking among blogs.