Comments are a funny thing, at first when I started writing, I read them and never thought much more about it, but over time, I have taken to answering them most of the time, just because I think folks like to see that you are validating or at least reading their opinions. Sometimes I get good ideas from the comments, so I am pretty diligent in reading them.
I also have my comments moderated because early on my site was INUNDATED with spam comments. Still, thanks to a useful plug-in AKISMET, a large number of SPAM comments have been scraped away. I also have added a CAPTCHA plug-in as well SI Captcha Anti-SPAM which has minimized the number of garbage comments that get to where I have to Moderate them.
I also moderate all comments to make sure anything that slips through, I know what goes in as a comment. Show a dialogue with your readers and they will reward you by coming back to see what else you have said. As for all the Internet Trolls out there, drop by as well. I try to answer most comments