Fan comments on the episode pages are moderated, meaning that a new comment will not appear to the public until either one of the Global Moderator or I approve it. I try to check for new submittals at least once a day, so it rarely takes longer than 24 hours before one of us has taken a look at it. I usually approve them as soon as I take a look, although I may occasionally "clean up" an entry's format before approving it. I normal approve all of them, unless it's a really pointless post (for example, if it is just something like "Great short!")
The fan comments are one of the oldest features of the site, and actually predate the message boards. At one point, though, they were blended into the message boads, and they ended up getting filled with garbage posts (I remember one prize idiot who made posts consisting of just "Clowns gonna get me!" over and over again, up to 100 times in a single post!) There were also several "flamewars" and other assorted nonsense. When I re-launched the site on Curly's bithday last year (it was down for a couple of months, after I screwed up the database and had to rebuild it), I left the comments off at first while I cleaned out most of the crap. When I relaunched them a few month's later, I made them strictly moderated so that won't happen again.
To make it easier for everyone to see what's been added to the site, I've put a new section on the Home page called "Recent Updates', which will also list any new fan comments that have been submitted within the past 2 weeks. There's also a link to it on the Home menu, at the top of every page.