If you post a comment and don’t see it up on the site immediately, that means it’s been caught by Blogger’s overactive spam filter, which unfortunately I can’t shut off. Unless your comment is incredibly foul or otherwise violates my fairly liberal comments policy, I will un-filter it as soon as I see it. Sometimes this will happen quickly, sometimes slowly. I’m not always online.
If your comment is posted and then later vanishes, that means I deliberately deleted it. But unless you’ve posted something truly awful, or spammy, or you’re among the tiny number of those I’ve banned (which can be counted on one hand), this isn’t going to happen to you.