Check the Akismet spam folder

Akismet is a very efficient spam filter plugin, but it is not perfect. Usually, it will block 1 legit comment out of 100 spam comments, translating into 1 or 2 legit comments being blocked every week on my case.

Make sure you check the Akismet spam folder once in a while to recover those legit comments, preferably once a week. Should a reader notice that his comment did not appear on the site it is very probable that he will get discouraged from commenting again.