Difficulties posting comments

I just received a comment from someone indicating several of his previous comments have not been posted, and he wondered if I deleted them.  He's not the first to mention this issue.

Just so everyone knows, I very, very seldom delete comments unless they're vulgar, full of profanity, or advertising something.  So if your comments are not getting posted, it means I never got them.  Honestly!  They're not in my spam folder either - they just seem to disappear.   I'm not kidding, even my husband posted a comment this morning and it hasn't come through for moderation.  Where it went, I have no idea.

So if your comments aren't getting posted, it doesn't mean I'm deleting them, it simply means I haven't seen them.  We've had one or two people figure out what the problem was on their end, so if they'd be kind enough to post how they overcame those issues, I'd be grateful.  Thanks!