There are a two reasons why your comments might not appear after you have posted them.
First, if you are a new reader then your comment is held for my approval before it is allowed to go up. This is to prevent spam.
Second, if you have commented before, then it is possible that our spam filter has intercepted your comment and held it for my approval or deletion. As our spam filter has blocked over 1,574,678 spam comments you can see why using this filter is important. I will delete all duplicate comments as I don’t have time to compare each one to the other to see if they are the same or different. I check spam and comments 4 or 5 times a day so a little patience will be appreciated.
The third reason is sometimes the site is rather slow and you wonder if you did hit the submit button properly, and then you hit it again just to be sure.