Always acknowledge a comment on your blog and respond to the commentator, preferably at his own blog. Its great to reciprocate the gesture.
An interactive style of writing will help you gain readers, but steer clear of SMS lingo if you want to be taken seriously.
E-commerce bloggers must carefully write keeping their audience in mind. Everything you post on your blog will speak for your product or service. Your interaction with bloggers in comments and otherwise will give you a direction.