I was getting an influx of spam. So instead of spending extra time in removing it, or paying for a plugin to do it for me, I decided to disable the comments. I hope to reactivate them some day, but I haven't found a solution or had the time. It has been suggested that I start a forum for discussions, but that also opens the site up to spam. Comments are still active on my mirror sites, though.
I confess, Lisa Frank crossed my mind too, but I didn't know if you were old enough to take that as an insult or not (it totally wouldn't have been, cause those dolphin/unicorn binders were super-rad).