I have turned comment moderation on on my blog. This means that from now on a comment only appears on my blog after I have approved it. The reason is that the spam comments were getting out of hand. On some days I had up to 50 spam comments, and manually deleting them cost me too much time.
It does not mean that I will only approve comments that are favorable, as long as it is not spam the comment should appear on my blog as soon as I get a chance to approve it (which is basically whenever I am online).